Les auteurs remercient le personnel du noyau Morphologie et d&#39;imagerie, du noyau génétique moléculaire (Département d&#39;ophtalmologie et des sciences visuelles) et de la Génétique de la souris de base à la Washington University School of Medicine à St. Louis. Les auteurs sont soutenus par le programme de petites subventions du centre McDonnell cellulaire et neurobiologie moléculaire, le Centre Espoir pour les troubles neurologiques, le National Eye Institute (# R01EY022632 DH), un National Eye Institute Core Center Grant (# P30EY002687) et une subvention sans restriction de la recherche pour prévenir la cécité au Département d&#39;ophtalmologie et des sciences visuelles.

Déclaration éthique: procédures impliquant des sujets animaux ont été approuvés par le Comité institutionnel de protection des animaux et l&#39;utilisation (IACUC) à l&#39;Université de Washington à St. Louis. 1. élevage de souris et de génotypage <ol><li> Race Tg (CAG-LacZ / EGFP-KASH2) souris avec Tg (PCP2-Cre) pour produire des souris Tg (PCP2Cre CAG-EGFP / KASH2) 19,20. Note: Alors que le reste de ce protocole met l&#39;accent sur l&#39;utilisation de la ligne Tg (PCP2-Cre) de la souris pour restreindre EGFP-KASH2 expression aux cellules de Purkinje dans le cervelet, une procédure similaire peut être suivi avec un autre Tg (Cre) de la souris ( Figure 2A). </li><li> Effectuer génotypage pour identifier les chiots abritant deux transgènes EGFP et la CRE comme décrit précédemment 19. </li></ol> 2. Préparation des matériaux pour la dissection et de tissus Collection <ol><li> Préparez 100 ml de saccharose à 30% dans du PBS (30 g de saccharose / 100 ml de PBS 1x) et conserver à -20 ° C. Le jour de tissu harvesting, dégel et la charge ~ 30-35 ml de solution de saccharose dans une seringue de 35 ml pour les perfusions transcardial. </li><li> Préparer 40 ml de PFA à 4% dans du PBS (10 ml de 16% de paraformaldehyde et 30 ml de PBS). Charge ~ 30-35 ml de PFA à 4% dans une seringue de 35 ml pour les perfusions transcardial. </li><li> Remplir un tissu plaque de culture de 10 cm avec 10 ml de PBS pour la dissection de tissus. </li><li> Préparer un cocktail kétamine / xylazine constitué de 16 mg / ml de kétamine et de 3 mg / ml de xylazine. </li><li> Préparer une solution d&#39;éthanol à 70% pour la dissection. </li></ol> 3. Dissection et collecte de tissus <ol><li> En utilisant une seringue de 1 ml, 500 pi d&#39;injecter le cocktail de kétamine / xylazine par 25 g de poids corporel et attendre ~ 15 min. Vous pouvez également utiliser une autre méthode de sédation institutionnel approuvé qui est approprié pour le système biologique d&#39;intérêt. </li><li> Sur la sédation, pincez doucement la patte arrière pour confirmer l&#39;absence de réponse de la douleur, épingler tous les pattes sur un plateau de styromousse avec la face dorsale de lasouris vers le bas. </li><li> Pulvériser l&#39;abdomen avec 70% d&#39;éthanol et de faire une incision de l&#39;abdomen inférieur vers le haut de la cage thoracique pour avoir accès au cœur. </li><li> Faire une petite incision dans l&#39;oreillette droite du cœur et insérer la seringue contenant la solution de saccharose à 30% dans le ventricule gauche du cœur. </li><li> Perfuser la solution à un débit de ~ 2-5 ml par min. Une fois vide, retirer la seringue et répéter avec la solution PFA 4%. </li><li> Détacher la souris à partir du plateau de styromousse et décapiter pour accéder au cerveau. </li><li> Retirer la peau autour de la tête de l&#39;animal à l&#39;aide de pinces et ciseaux. Percer un trou dans la partie postérieure du crâne avec une aiguille et retirer délicatement le crâne avec des ciseaux et des pinces à dissection. </li><li> Une fois que le cerveau est clairement accessible, utiliser une pince pour enlever le cervelet et le placer dans PBS. Couper en deux le cervelet dans le plan sagittal avec un scalpel et le transférer à la solution de saccharose à 30% pendant une nuit à 4 ° C. Remarque: Pour prépsont des coupes en paraffine, fixent le cervelet pendant une nuit à 4 ° C dans 4% de PFA avant l&#39;incorporation de tissu et la coupe. </li></ol> 4. Traitement des tissus et la coupe <ol><li> Préparer une suspension de glace sèche et le butane 2-méthyl. Laisser la température du bain à équilibrer pendant 5 min. </li><li> Remplissez un cryomoule avec le composé PTOM et placer une moitié du cervelet bissectée dans le moule. </li><li> En utilisant un microscope de dissection et d&#39;une paire de pince de la position du cervelet de sorte que la surface coupée en deux (près de la ligne médiane du cervelet) est orientée vers le haut. </li><li> Transférer le cryomoule à la suspension de la glace sèche pendant 5 min jusqu&#39;à ce que l&#39;Ordre a formé composé d&#39;une matrice solide blanc autour de l&#39;échantillon de tissu. Remarque: Les spécimen congelé peuvent désormais être conservés à -20 ° C si nécessaire. </li><li> Étiquette pré-traitée diapositives de poly-lysine pour la collecte des coupes de tissus et de préparer le cryostat selon les instructions du fabricant afin de recueillir 15 um sections de la Cèrebellum. Pour collecter les sections, contactez attentivement la section PTOM à la face revêtue de la lame de poly-lysine. Afin de préserver l&#39;orientation de la section, ne pas tourner la diapositive lors de cette étape. </li><li> Coupes de tissus de magasin -20 ° C à jusqu&#39;à procéder à la coloration et l&#39;imagerie. </li></ol> 5. Coloration et imagerie du cervelet Sections <ol><li> Préparer les solutions suivantes avant la coloration de tissus: ~ 50 ml de PBS ~ 5-10 ml de PFA à 4% dans du PBS ~ 10-20 ml de 0,5% de Triton X-100 de sérum d&#39;âne, à 10% dans du PBS </li><li> Sections cérébelleux dégel. Surtout, minimiser leur exposition à une source de lumière continue et intense pour éviter la décoloration de l&#39;EGFP. </li><li> En utilisant un stylo de barrière hydrophobe, dessinez un rectangle autour des sections de tissus. </li><li> Post-fixer les sections avec PFA 4% pendant 5 min. Utilisez assez de liquide pour couvrir l&#39;ensemble de la zone délimitée par la barrière hydrophobe (généralement ~ 500 pi). Aide d&#39;un aspirateur ou d&#39;une pipette, REdéplacer le fixateur en faisant particulièrement attention à ne pas déranger les coupes de tissus. </li><li> Avec une pipette, appliquer doucement PBS sur la diapositive sans déranger les coupes de tissus. Après 5 min utiliser l&#39;aspirateur ou une pipette pour enlever avec précaution le liquide. Répétez la PBS rincer un total de trois fois. </li><li> En utilisant une pipette, appliquez soigneusement la dilution appropriée d&#39;anticorps primaires (3 pi Calbindin et / ou d&#39;anticorps Nesprin2 par 900 pi de solution) dans 0,5% de Triton X-100, le sérum de l&#39;âne de 10% dans le PBS. Incuber pendant une heure à la température ambiante dans l&#39;obscurité. Remarque: EGFP-KASH2 restera visible par microscopie à fluorescence directe sur des coupes congelées, sans qu&#39;il soit nécessaire d&#39;utiliser un anticorps anti-EGFP. Toutefois, si des sections de paraffine ont été préparés, l&#39;imagerie de l&#39;EGFP-KASH2 nécessite immunodétection avec un anticorps anti-EGFP. </li><li> Retirer la solution d&#39;anticorps et rincer avec du PBS à trois reprises. </li><li> Préparation 1: 1000 d&#39;anticorps secondaire dilutions Alexa Fluor-0,5 en% de Triton X-100,10% de sérum de âne dans PBS et de stocker dans l&#39;obscurité. </li><li> Retirez délicatement le rinçage final PBS et appliquer la dilution d&#39;anticorps secondaire pendant une heure dans l&#39;obscurité. </li><li> Retirer la solution d&#39;anticorps secondaire, rincer et laver la section trois fois. Si nécessaire, appliquer un colorant nucléaire, tels que le DAPI (~ 300 nM), au cours de la première application du PBS. </li><li> Supprimer complètement la solution de PBS à partir autour du tissu et le lieu ~ 5-7 pi de milieu de montage sur la section de tissu. Placez une lamelle de verre sur le dessus de la section de tissu et mettre de côté pour ~ 15-30 min à température ambiante dans l&#39;obscurité. </li><li> Utilisation d&#39;un microscope à fluorescence équipé des filtres appropriés pour visualiser EGFP ainsi que d&#39;autres longueurs d&#39;onde appropriées pour les anticorps secondaires utilisés dans les étapes 5.8 / 5.9. Dans tranches de cervelet, utilisez un objectif 20X pour voir jantes nucléaires EGFP-KASH2. </li></ol>

<ol>
	<li>Hutchison, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamins:+building+blocks+or+regulators+of+gene+expression?+Nature+reviews.">Lamins: building blocks or regulators of gene expression? Nature reviews.</a> Molecular cell biology. 3, 848-858 (2002).</li><li>Stuurman, N., Heins, S., Aebi, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+lamins:+their+structure,+assembly,+and+interactions.">Nuclear lamins: their structure, assembly, and interactions.</a> Journal of structural biology. 122, 42-66 (1998).</li><li>Crisp, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coupling+of+the+nucleus+and+cytoplasm:+role+of+the+LINC+complex.">Coupling of the nucleus and cytoplasm: role of the LINC complex.</a> The Journal of cell biology. 172, 41-53 (2006).</li><li>Haque, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SUN1+interacts+with+nuclear+lamin+A+and+cytoplasmic+nesprins+to+provide+a+physical+connection+between+the+nuclear+lamina+and+the+cytoskeleton.">SUN1 interacts with nuclear lamin A and cytoplasmic nesprins to provide a physical connection between the nuclear lamina and the cytoskeleton.</a> Molecular and cellular biology. 26, 3738-3751 (2006).</li><li>Hodzic, D. M., Yeater, D. B., Bengtsson, L., Otto, H., Stahl, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sun2+is+a+novel+mammalian+inner+nuclear+membrane+protein.">Sun2 is a novel mammalian inner nuclear membrane protein.</a> The Journal of biological chemistry. 279, 25805-25812 (2004).</li><li>Starr, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KASH+and+SUN+proteins.">KASH and SUN proteins.</a> Current biology : CB. 21, R414-R415 (2011).</li><li>Mellad, J. A., Warren, D. T., Shanahan, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nesprins+LINC+the+nucleus+and+cytoskeleton.">Nesprins LINC the nucleus and cytoskeleton.</a> Current opinion in cell biology. 23, 47-54 (2011).</li><li>Fridolfsson, H. N., Starr, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinesin-1+and+dynein+at+the+nuclear+envelope+mediate+the+bidirectional+migrations+of+nuclei.">Kinesin-1 and dynein at the nuclear envelope mediate the bidirectional migrations of nuclei.</a> The Journal of cell biology. 191, 115-128 (2010).</li><li>Meyerzon, M., Fridolfsson, H. N., Ly, N., McNally, F. J., Starr, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UNC-83+is+a+nuclear-specific+cargo+adaptor+for+kinesin-1-mediated+nuclear+migration.">UNC-83 is a nuclear-specific cargo adaptor for kinesin-1-mediated nuclear migration.</a> Development. 136, 2725-2733 (2009).</li><li>Padmakumar, V. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enaptin,+a+giant+actin-binding+protein,+is+an+element+of+the+nuclear+membrane+and+the+actin+cytoskeleton.">Enaptin, a giant actin-binding protein, is an element of the nuclear membrane and the actin cytoskeleton.</a> Experimental cell research. 295, 330-339 (2004).</li><li>Roux, K. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nesprin+4+is+an+outer+nuclear+membrane+protein+that+can+induce+kinesin-mediated+cell+polarization.">Nesprin 4 is an outer nuclear membrane protein that can induce kinesin-mediated cell polarization.</a> Proceedings of the National Academy of Sciences of the United States of America. 106, 2194-2199 (2009).</li><li>Wilhelmsen, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=a+novel+outer+nuclear+membrane+protein,+associates+with+the+cytoskeletal+linker+protein+plectin.">a novel outer nuclear membrane protein, associates with the cytoskeletal linker protein plectin.</a> The Journal of cell biology. 171, 799-810 (2005).</li><li>Wilson, M. H., Holzbaur, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nesprins+anchor+kinesin-1+motors+to+the+nucleus+to+drive+nuclear+distribution+in+muscle+cells.">Nesprins anchor kinesin-1 motors to the nucleus to drive nuclear distribution in muscle cells.</a> Development. 142, 218-228 (2015).</li><li>Yu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KASH+protein+Syne-2/Nesprin-2+and+SUN+proteins+SUN1/2+mediate+nuclear+migration+during+mammalian+retinal+development.">KASH protein Syne-2/Nesprin-2 and SUN proteins SUN1/2 mediate nuclear migration during mammalian retinal development.</a> Human molecular genetics. 20, 1061-1073 (2011).</li><li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Syne-1+and+Syne-2+play+crucial+roles+in+myonuclear+anchorage+and+motor+neuron+innervation.">Syne-1 and Syne-2 play crucial roles in myonuclear anchorage and motor neuron innervation.</a> Development. 134, 901-908 (2007).</li><li>Zhang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nesprin+1+is+critical+for+nuclear+positioning+and+anchorage.">Nesprin 1 is critical for nuclear positioning and anchorage.</a> Human molecular genetics. 19, 329-341 (2010).</li><li>Stewart-Hutchinson, P. J., Hale, C. M., Wirtz, D., Hodzic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+requirements+for+the+assembly+of+LINC+complexes+and+their+function+in+cellular+mechanical+stiffness.">Structural requirements for the assembly of LINC complexes and their function in cellular mechanical stiffness.</a> Experimental cell research. 314, 1892-1905 (2008).</li><li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SUN1/2+and+Syne/Nesprin-1/2+complexes+connect+centrosome+to+the+nucleus+during+neurogenesis+and+neuronal+migration+in+mice.">SUN1/2 and Syne/Nesprin-1/2 complexes connect centrosome to the nucleus during neurogenesis and neuronal migration in mice.</a> Neuron. 64, 173-187 (2009).</li><li>Razafsky, D., Hodzic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+and+tissue-specific+disruption+of+LINC+complexes+in+vivo.">Temporal and tissue-specific disruption of LINC complexes in vivo.</a> Genesis. 52, 359-365 (2014).</li><li>Razafsky, D., Hodzic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+variant+of+Nesprin1+giant+devoid+of+KASH+domain+underlies+the+molecular+etiology+of+autosomal+recessive+cerebellar+ataxia+type+I.">A variant of Nesprin1 giant devoid of KASH domain underlies the molecular etiology of autosomal recessive cerebellar ataxia type I.</a> Neurobiology of disease. 78, 57-67 (2015).</li><li>Razafsky, D., Blecher, N., Markov, A., Stewart-Hutchinson, P. J., Hodzic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LINC+complexes+mediate+the+positioning+of+cone+photoreceptor+nuclei+in+mouse+retina.">LINC complexes mediate the positioning of cone photoreceptor nuclei in mouse retina.</a> PloS one. 7, e47180 (2012).</li><li>Razafsky, D. S., Ward, C. L., Kolb, T., Hodzic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+regulation+of+linkers+of+the+nucleoskeleton+to+the+cytoskeleton+during+mouse+postnatal+retinogenesis.">Developmental regulation of linkers of the nucleoskeleton to the cytoskeleton during mouse postnatal retinogenesis.</a> Nucleus. 4, 399-409 (2013).</li></ol>

Les auteurs ont rien à révéler.

L&#39;étape la plus critique pour étudier avec succès le rôle de complexes CLIC in vivo utilise le (/ EGFP-KASH2 CAG-LacZ) modèle Tg est d&#39;identifier une ligne appropriée de la souris Cre (s). En effet, si Cre est actif dans d&#39;autres types cellulaires impliqués dans les voies similaires, il peut compliquer l&#39;interprétation des résultats. Par conséquent, il est important d&#39;examiner les cellules voisines, comme illustré ici dans les couches cellulaires et moléculaires granulaires du ce...

L&#39;enveloppe nucléaire (NE) sépare le nucléoplasme à partir du cytoplasme. Il est composé d&#39;une membrane nucléaire interne et externe (INM et ONM, respectivement) qui se connectent à des pores nucléaires. La lumière délimitée par deux membranes est appelé l&#39;espace périnucléaire (PNS). L&#39;ONM est une extension du réticulum endoplasmique rugueux (ER) et l&#39;INM adhère à la lamina nucléaire, un maillage de l&#39;énergie nucléaire de type V filaments intermédiaires représenté par A et de type B lamines 1,2. Lieurs du cytosquelette et Nucleoskeleton (CLIC) sont des assemblages macromoléculaires complexes qui couvrent l&#39;ensemble de l&#39;enveloppe nucléaire de se connecter physiquement à l&#39;intérieur du noyau de filaments du cytosquelette et des moteurs moléculaires (Figure 1A). Ils se composent d&#39;interactions entre les motifs conservés qui caractérisent l&#39;évolution, deux familles de protéines transmembranaires intégrante du NE: Sun (SAD1 / Unc84) des protéines et des Nesprins (SPectRINS enveloppe nucléaire). Chez les mammifères, Sun1 et Sun2 are protéines transmembranaires de l&#39;INM dont la région nucléoplasmique N-terminal interagit directement avec A et de type B lamines 3-5. De l&#39;autre côté de l&#39;INM, dans le PNS, protéines Sun Harbor un tronçon évolutif conservé de ~ 150 acides aminés C-terminal appelé le domaine soleil. SUN domaines interagissent directement avec l&#39;évolution conservé KASH (Klarsicht / Anc-1, Syne homologie) domaine, la signature moléculaire de Nesprins. KASH domaines sont constitués par un tronçon de ~ 30 acides aminés C-terminal qui fait saillie dans le PNS suivi d&#39;un domaine transmembranaire 6. Au moins quatre gènes distincts (Nesprin1-4 Nesprin) codent KASH contenant des protéines qui localisent au NE 7. Les régions cytoplasmiques de Nesprins, dont les tailles varient de ~ 50 kDa (Nesprin4) à une étonnante 1.000 kDa (Nesprin1 géant), contiennent spectrine multiples répétitions ainsi que des motifs spécifiques permettant leur interaction avec les composants du cytosquelette tels que l&#39;actine, plectine et moteurs moléculaires 8- 13. &lt;p class = &quot;jove_content&quot;&gt; Études chez les vertébrés et les invertébrés ont montré que Lamin / moteurs moléculaires Sun / Nesprin / constituent un &quot;axe&quot; évolutif conservé le contrôle de la migration nucléaire et d&#39;ancrage. Plusieurs modèles de souris knock-out (KO) de CLIC composants complexes ont été décrites et ont contribué à fournir un cadre pour comprendre le rôle des protéines Sun et Nesprin au cours du développement des mammifères NE 9,14,15. Cependant, ces modèles présentent plusieurs inconvénients importants, et plus particulièrement: 1) difficulté à interpréter phénotypes dues à la cellule des effets non-autonomes, 2) la difficulté de distinguer les contributions phénotypiques de KASH contenant vs KASH-moins Nesprin isoformes 16, 3) la redondance fonctionnelle des protéines Sun et Nesprin à la NE dans de nombreux types de cellules nécessite des programmes de sélection complexes pour inactiver toutes les interactions SUN-Kash chez la souris 17 et 4) la létalité périnatale de souris déficientes pour le KASH-domaine à la foisNesprins1 et 2 se oppose à l&#39;analyse des phénotypes adultes 18. Ce protocole décrit un nouveau modèle de souris conçu pour perturber toutes les interactions SUN-Kash in vivo, dans une cellule de façon autonome et régulée par le développement, contournant ainsi la plupart des inconvénients décrits ci-dessus. Ce modèle de souris Cre / sur la base de LOX-repose sur deux concepts importants: 1) le domaine KASH de toute protéine Nesprin connu est suffisante pour cibler EGFP vers NE dans les systèmes de culture de cellules et 2) les domaines de SUN interagir pêle-mêle avec des domaines KASH, ainsi surexpression de tout domaine KASH va saturer tous les domaines de SUN endogènes et inactiver complexes CLIC de manière dominante négative 17 (figure 1B). Ce protocole décrit la récolte des tissus et des étapes de traitement utilisées pour confirmer l&#39;interruption de toutes les interactions SUN-Kash dans les cellules de Purkinje du cervelet.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Sucrose</td>
			<td>Sigma Aldrich</td>
			<td>S0389</td>
			<td></td>
		</tr>
		<tr>
			<td>10x PBS</td>
			<td>Gibco</td>
			<td>14200-075</td>
			<td></td>
		</tr>
		<tr>
			<td>16% Paraformaldehyde Solution</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td></td>
		</tr>
		<tr>
			<td>OCT Compound</td>
			<td>Tissue-Tek</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>Adhesion Slides</td>
			<td>StatLab</td>
			<td>M1000W</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey Serum</td>
			<td>Sigma Aldrich</td>
			<td>D9663</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma Aldrich</td>
			<td>T9284</td>
			<td></td>
		</tr>
		<tr>
			<td>ImmuEdge Pen</td>
			<td>Vector Laboratories</td>
			<td>H-4000</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Calbindin Antibody</td>
			<td>Sigma Aldrich</td>
			<td>C9848</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-EGFP Antibody</td>
			<td>Abcam</td>
			<td>ab13970</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Nesprin2 Antibody</td>
			<td></td>
			<td></td>
			<td>Previously described in Ref. 21</td>
		</tr>
		<tr>
			<td>Fluorescent Mounting Media</td>
			<td>Dako</td>
			<td>S3023</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methyl butane</td>
			<td>Sigma Aldrich</td>
			<td>O3551</td>
			<td></td>
		</tr>
	</tbody>
</table>

validation of a mouse model to disrupt linc complexes in a cell-specific manner

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the Nucleoskeleton and Cytoskeleton (LINC complexes). These protein scaffolds span the nuclear envelope and connect the interior of the nucleus to components of the surrounding cytoplasmic cytoskeleton. LINC complexes consist of two evolutionary-conserved protein families, Sun proteins and Nesprins that harbor C-terminal molecular signature motifs called the SUN and KASH domains, respectively. Sun proteins are transmembrane proteins of the inner nuclear membrane whose N-terminal nucleoplasmic domain interacts with the nuclear lamina while their C-terminal SUN domains protrudes into the perinuclear space and interacts with the KASH domain of Nesprins. Canonical Nesprin isoforms have a variable sized N-terminus that projects into the cytoplasm and interacts with components of the cytoskeleton. This protocol describes the validation of a dominant-negative transgenic mouse strategy that disrupts endogenous SUN/KASH interactions in a cell-type specific manner. Our approach is based on the Cre/Lox system that bypasses many drawbacks such as perinatal lethality and cell nonautonomous phenotypes that are associated with germline models of LINC complex inactivation. For this reason, this model provides a useful tool to understand the role of LINC complexes during development and homeostasis in a wide array of tissues.

Ce protocole illustre l&#39;utilité de la (/ EGFP-KASH2 CAG-LacZ) Tg modèle de souris pour restreindre EGFP-KASH2 expression à l&#39;aide de cellules cérébelleuses de Purkinje souris Tg (PCP2-Cre). Dans Tg (PCP2Cre CAG-EGFP / KASH2) progéniture, le cadre de lecture ouvert LacZ / V5 est excisée à P6 par la Cre recombinase ce qui conduit à l&#39;expression de EGFP-KASH2 spécifiquement ciblées sur les cellules de Purkinje (figure 2A). Comme prévu, EGFP-KASH2 est destiné à l&#39;env...

Watch this Scientific Journal Video about Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner at JoVE.com

Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner

Nuclear envelope proteins play a central role in many basic biological processes and have been implicated in a variety of human diseases. This protocol describes a new Cre/Lox-based mouse model that allows for the spatiotemporal control of LINC complexes disruption.

Validation d&#39;un modèle de souris de perturber CLIC complexes de façon spécifique à la cellule

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the ...

validation-mouse-model-to-disrupt-linc-complexes-cell-specific

Research

JoVE Journal

Biology

7.3K vues.  Washington University in St. Louis School of Medicine. Nuclear envelope proteins play a central role in many basic biological processes and have been implicated in a variety of human diseases. This protocol describes a new Cre/Lox-based mouse model that allows for the spatiotemporal control of LINC complexes disruption.

Vidéo: Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson's Disease Genes

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations at risk. In the process of attempting to identify novel genetic factors associated with PD, scientists have generated many lists of candidate genes, polymorphisms, and proteins that represent important advances, but these leads remain mechanistically undefined. Our work is aimed toward significantly narrowing such lists by exploiting the advantages of a simple animal model system. While humans have billions of neurons, the microscopic roundworm Caenorhabditis elegans has precisely 302, of which only eight produce dopamine (DA) in hemaphrodites. Expression of a human gene encoding the PD-associated protein, alpha-synuclein, in C. elegans DA neurons results in dosage and age-dependent neurodegeneration.
Worms expressing human alpha-synuclein in DA neurons are isogenic and express both GFP and human alpha-synuclein under the DA transporter promoter (Pdat-1). The presence of GFP serves as a readily visualized marker for following DA neurodegeneration in these animals. We initially demonstrated that alpha-synuclein-induced DA neurodegeneration could be rescued in these animals by torsinA, a protein with molecular chaperone activity 1. Further, candidate PD-related genes identified in our lab via large-scale RNAi screening efforts using an alpha-synuclein misfolding assay were then over-expressed in C. elegans DA neurons. We determined that five of seven genes tested represented significant candidate modulators of PD as they rescued alpha-synuclein-induced DA neurodegeneration 2. Additionally, the Lindquist Lab (this issue of JoVE) has performed yeast screens whereby alpha-synuclein-dependent toxicity is used as a readout for genes that can enhance or suppress cytotoxicity. We subsequently examined the yeast candidate genes in our C. elegans alpha-synuclein-induced neurodegeneration assay and successfully validated many of these targets 3, 4.
Our methodology involves generation of a C. elegans DA neuron-specific expression vector using recombinational cloning of candidate gene cDNAs under control of the Pdat-1 promoter. These plasmids are then microinjected in wild-type (N2) worms, along with a selectable marker for successful transformation. Multiple stable transgenic lines producing the candidate protein in DA neurons are obtained and then independently crossed into the alpha-synuclein degenerative strain and assessed for neurodegeneration, at both the animal and individual neuron level, over the course of aging.

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson&#039;s Disease Genes

This video demonstrates how to use C. elegans to assess dopaminergic neuron neurodegeneration as a model for Parkinson's disease. Furthermore, genetic screens are used to identify factors that either enhance degeneration or are neuroprotective.

Application d&#39;une Assay C. elegans dégénérescence des neurones dopaminergiques pour la validation du potentiel de la maladie de Parkinson gènes

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations ...

Recherche

Biologie

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

L&#39;imagerie in vivo et des traitements thérapeutiques dans un modèle de souris orthotopique de cancer des ovaires

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism

The folding and assembly of proteins is essential for protein function, the long-term health of the cell, and longevity of the organism. Historically, the function and regulation of protein folding was studied in vitro, in isolated tissue culture cells and in unicellular organisms. Recent studies have uncovered links between protein homeostasis (proteostasis), metabolism, development, aging, and temperature-sensing. These findings have led to the development of new tools for monitoring protein folding in the model metazoan organism Caenorhabditis elegans. In our laboratory, we combine behavioral assays, imaging and biochemical approaches using temperature-sensitive or naturally occurring metastable proteins as sensors of the folding environment to monitor protein misfolding. Behavioral assays that are associated with the misfolding of a specific protein provide a simple and powerful readout for protein folding, allowing for the fast screening of genes and conditions that modulate folding. Likewise, such misfolding can be associated with protein mislocalization in the cell. Monitoring protein localization can, therefore, highlight changes in cellular folding capacity occurring in different tissues, at various stages of development and in the face of changing conditions. Finally, using biochemical tools ex vivo, we can directly monitor protein stability and conformation. Thus, by combining behavioral assays, imaging and biochemical techniques, we are able to monitor protein misfolding at the resolution of the organism, the cell, and the protein, respectively.

Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism

To study the relationship between protein homeostasis, stress and aging, we monitored changes in protein folding by following protein dysfunction, protein localization in the cell and protein stability at the organismal, cellular and protein levels, using the genetically tractable metazoan Caenorhabditis elegans as a model system.

The folding and assembly of proteins is essential for protein function, the long-term health of the cell, and longevity of the organism. Historically, the ...

Nephrotoxin Microinjection in Zebrafish to Model Acute Kidney Injury

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid decline in renal function and development of the clinical syndrome known as acute kidney injury (AKI). Pharmacological agents used to treat medical circumstances ranging from bacterial infection to cancer, when administered individually or in combination with other drugs, can initiate AKI. Zebrafish are a useful animal model to study the chemical effects on renal function in vivo, as they form an embryonic kidney comprised of nephron functional units that are conserved with higher vertebrates, including humans. Further, zebrafish can be utilized to perform genetic and chemical screens, which provide opportunities to elucidate the cellular and molecular facets of AKI and develop therapeutic strategies such as the identification of nephroprotective molecules. Here, we demonstrate how microinjection into the zebrafish embryo can be utilized as a paradigm for nephrotoxin studies.

Renal injuries incurred from nephrotoxins, which include drugs ranging from antibiotics to chemotherapeutics, can result in complex disorders whose pathogenesis remains incompletely understood. This protocol demonstrates how zebrafish can be used for disease modeling of these conditions, which can be applied to the identification of renoprotective measures.

Néphrotoxine microinjection dans Zebrafish au Modèle lésion rénale aiguë

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid ...

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

TRANS-intérieur cellulaire massive Injection de cellules souches embryonnaires conduit à des taux plus élevés de chimérisme

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

A Flow Cytometry-based Assay to Identify Compounds That Disrupt Binding of Fluorescently-labeled CXC Chemokine Ligand 12 to CXC Chemokine Receptor 4

Pharmacological targeting of G protein-coupled receptors (GPCRs) is of great importance to human health, as dysfunctional GPCR-mediated signaling contributes to the progression of many diseases. The ligand/receptor pair CXC chemokine ligand 12 (CXCL12)/CXC chemokine receptor 4 (CXCR4) has raised significant clinical interest, for instance as a potential target for the treatment of cancer and inflammatory diseases. Small molecules as well as therapeutic antibodies that specifically target CXCR4 and inhibit the receptor&#39;s function are therefore considered to be valuable pharmacological tools. Here, a flow cytometry-based cellular assay that allows identification of compounds (e.g., small molecules) that abrogate CXCL12 binding to CXCR4, is described. Essentially, the assay relies on the competition for receptor binding between a fixed amount of fluorescently labeled CXCL12, the natural chemokine agonist for CXCR4, and unlabeled compounds. Hence, the undesirable use of radioactively labeled probes is avoided in this assay. In addition, living cells are used as the source of receptor (CXCR4) instead of cell membrane preparations. This allows easy adaptation of the assay to a plate format, which increases the throughput. This assay has been shown to be a valuable generic drug discovery assay to identify CXCR4-targeting compounds. The protocol can likely be adapted to other GPCRs, at least if fluorescently labeled ligands are available or can be generated. Prior knowledge concerning the intracellular signaling pathways that are induced upon activation of these GPCRs, is not required.

A flow cytometry-based cellular binding assay is described that is primarily used as a screening tool to identify compounds that inhibit the binding of a fluorescently labeled CXC chemokine ligand 12 (CXCL12) to the CXC chemokine receptor 4 (CXCR4).

Un test Flow Cytometry d’identifier des composés qui perturbent la fixation du Ligand de chimiokines CXC fluorescent marqué 12 au récepteur de chimiokines CXC 4

Pharmacological targeting of G protein-coupled receptors (GPCRs) is of great importance to human health, as dysfunctional GPCR-mediated signaling ...

A Mouse Model of Intestinal Partial Obstruction

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including tumorous growths. However, the cellular remodeling mechanisms involved in, and caused by, intestinal obstructions are poorly understood. Several animal models of intestinal obstructions have been developed, but the mouse model is the most cost/time effective. The mouse model uses the surgical implantation of an intestinal partial obstruction (PO) that has a high mortality rate if it is not performed correctly. In addition, mice receiving PO surgery fail to develop hypertrophy if an appropriate blockade is not used or not properly placed. Here, we describe a detailed protocol for PO surgery which produces reliable and reproducible intestinal obstructions with a very low mortality rate. This protocol utilizes a surgically placed silicone ring that surrounds the ileum which partially blocks digestive movement in the small intestine. The partial blockage makes the intestine become dilated due to the halt of digestive movement. The dilation of the intestine induces smooth muscle hypertrophy on the oral side of the ring that progressively develops over 2 weeks until it causes death. The surgical PO mouse model offers an in vivo model of hypertrophic intestinal tissue useful for studying pathological changes of intestinal cells including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), PDGFR&#945;+, and neuronal cells during the development of intestinal obstruction.

Intestinal obstructions are a partial or complete blockage of the intestine that can cause severe abdominal pain, nausea, vomiting, and preventing the passage of stool. This procedure for creating intestinal partial obsructions in mice is reliable in studying the mechanisms underlying pathological cell growth and death in the intestine.

Un modèle de souris d’une Obstruction intestinale partielle

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.

Analyse de spectrométrie de masse pour identifier l’ubiquité de cenp-A marqué par EYFP (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer ...

A Mouse Model of Lumbar Spine Instability

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L3&#8211;L5 spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L4&#8211;L5 IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L5) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

We developed a lumbar intervertebral disc degeneration mouse model by resection of L3&#8211;L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Un modèle de souris de l’instabilité lombaire de colonne vertébrale

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding ...

Differentiated Mouse Adipocytes in Primary Culture: A Model of Insulin Resistance

Insulin resistance is a reduced effect of insulin on its target cells, usually derived from decreased insulin receptor signaling. Insulin resistance contributes to the development of type 2 diabetes (T2D) and other obesity-derived diseases of high prevalence worldwide. Therefore, understanding the mechanisms underlying insulin resistance is of great relevance. Several models have been used to study insulin resistance both in vivo and in vitro; primary adipocytes represent an attractive option to study the mechanisms of insulin resistance and identify molecules that counteract this condition and the molecular targets of insulin-sensitizing drugs. Here, we have established an insulin resistance model using primary adipocytes in culture treated with tumor necrosis factor-&#945; (TNF-&#945;).
Adipocyte precursor cells (APCs), isolated from collagenase-digested mouse subcutaneous adipose tissue by magnetic cell separation technology, are differentiated into primary adipocytes. Insulin resistance is then induced by treatment with TNF-&#945;, a proinflammatory cytokine that reduces the tyrosine phosphorylation/activation of members of the insulin signaling cascade. Decreased phosphorylation of insulin receptor (IR), insulin receptor substrate (IRS-1), and protein kinase B (AKT) are quantified by western blot. This method provides an excellent tool to study the mechanisms mediating insulin resistance in adipose tissue.

This protocol describes the isolation of mouse preadipocytes from subcutaneous fat, their differentiation into mature adipocytes, and the induction of insulin resistance. Insulin action is evaluated by the phosphorylation/activation of members of the insulin signaling pathway through western blot. This method allows direct determination of insulin resistance/sensitivity in primary adipocytes.

Adipocytes de souris différenciés en culture primaire: un modèle de résistance à l’insuline

Insulin resistance is a reduced effect of insulin on its target cells, usually derived from decreased insulin receptor signaling. Insulin resistance ...