Name: analysis of chromosome segregation, histone acetylation, and spindle morphology in horse oocytes
Uploaded: 2017-05-11T14:00:00
Description: Watch this Scientific Journal Video about Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes at JoVE.com

The authors would like to thank Fabrice Vincent for the support with laser scanning confocal microscopy (LSCM), and Philippe Barri&#232;re and Thierry Blard for performing daily ultrasound ovarian scanning and hCG injection. This work was supported in part by the &#34;Regione Sardegna and Regione Lombardia&#34; project &#34;Ex Ovo Omnia&#34; (Grant no. 26096200 to A. M. L.); the &#34;L&#39;Oreal Italia per le Donne e la Scienza 2012&#34; fellowship (Contract 2012 to F. F.), FP7-PEOPLE-2011- CIG, Research Executive Agency (REA) &#34;Pro-Ovum&#34; (Grant no. 303640 to V. L.); and by the Postdoctoral School of Agriculture and Veterinary Medicine, co-financed by the European Social Fund, Sectorial Operational Program for Human Resource Development 2007-2013 (Contract no. POSDRU/89/1.5/S/62371 to I. M.). The in vivo oocyte collection was financed by the Institut Fran&#231;ais du Cheval et de l&#39;Equitation.

All the procedures were approved by the Animal Care and Use Committee CEEA Val de Loire Number 19 and were performed in accordance with the Guiding Principles for the Care and Use of Laboratory Animals.
1. Oocyte Collection and In Vitro Maturation
<ol>
	<li>Ovum pick-up
	<ol>
		<li>Daily assess by ultrasound the diameter of ovarian follicles in a cohort of adult mares. At the emergence of a follicle &#8805;33 mm (dominant follicle), inject the mare with 1,500 IU of ...

<ol>
	<li>Dellenbach, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transvaginal,+sonographically+controlled+ovarian+follicle+puncture+for+egg+retrieval.">Transvaginal, sonographically controlled ovarian follicle puncture for egg retrieval.</a> Lancet. 1 (8392), 1467 (1984).</li><li>Humaidan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovarian+hyperstimulation+syndrome:+review+and+new+classification+criteria+for+reporting+in+clinical+trials.">Ovarian hyperstimulation syndrome: review and new classification criteria for reporting in clinical trials.</a> Hum Reprod. , (2016).</li><li>Pincus, G., Enzmann, E. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Comparative+Behavior+of+Mammalian+Eggs+in+Vivo+and+in+Vitro+:+I.+The+Activation+of+Ovarian+Eggs.">The Comparative Behavior of Mammalian Eggs in Vivo and in Vitro : I. The Activation of Ovarian Eggs.</a> J Exp Med. 62 (5), 665-675 (1935).</li><li>Emery, B. R., Wilcox, A. L., Aoki, V. W., Peterson, C. M., Carrell, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+oocyte+maturation+and+subsequent+delayed+fertilization+is+associated+with+increased+embryo+aneuploidy.">In vitro oocyte maturation and subsequent delayed fertilization is associated with increased embryo aneuploidy.</a> Fertil Steril. 84 (4), 1027-1029 (2005).</li><li>Nichols, S. M., Gierbolini, L., Gonzalez-Martinez, J. A., Bavister, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+in+vitro+maturation+and+age+on+oocyte+quality+in+the+rhesus+macaque+Macaca+mulatta.">Effects of in vitro maturation and age on oocyte quality in the rhesus macaque Macaca mulatta.</a> Fertil Steril. 93 (5), 1591-1600 (2010).</li><li>Requena, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+in-vitro+maturation+of+oocytes+on+aneuploidy+rate.">The impact of in-vitro maturation of oocytes on aneuploidy rate.</a> Reprod Biomed Online. 18 (6), 777-783 (2009).</li><li>Franciosi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+maturation+affects+chromosome+segregation,+spindle+morphology+and+acetylation+of+lysine+16+on+histone+H4+in+horse+oocytes.">In vitro maturation affects chromosome segregation, spindle morphology and acetylation of lysine 16 on histone H4 in horse oocytes.</a> Reprod Fertil Dev. , (2015).</li><li>Franciosi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+histone+H4+acetylation+during+in+vivo+versus+in+vitro+maturation+of+equine+oocytes.">Changes in histone H4 acetylation during in vivo versus in vitro maturation of equine oocytes.</a> Mol Hum Reprod. 18 (5), 243-252 (2012).</li><li>Choi, Y. H., Gibbons, J. R., Canesin, H. S., Hinrichs, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+medium+variations+(zinc+supplementation+during+oocyte+maturation,+perifertilization+pH,+and+embryo+culture+protein+source)+on+equine+embryo+development+after+intracytoplasmic+sperm+injection.">Effect of medium variations (zinc supplementation during oocyte maturation, perifertilization pH, and embryo culture protein source) on equine embryo development after intracytoplasmic sperm injection.</a> Theriogenology. , (2016).</li><li>Hendriks, W. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maternal+age+and+in+vitro+culture+affect+mitochondrial+number+and+function+in+equine+oocytes+and+embryos.">Maternal age and in vitro culture affect mitochondrial number and function in equine oocytes and embryos.</a> Reprod Fertil Dev. 27 (6), 957-968 (2015).</li><li>Carnevale, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mare+model+for+follicular+maturation+and+reproductive+aging+in+the+woman.">The mare model for follicular maturation and reproductive aging in the woman.</a> Theriogenology. 69 (1), 23-30 (2008).</li><li>Ginther, O. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mare:+a+1000-pound+guinea+pig+for+study+of+the+ovulatory+follicular+wave+in+women.">The mare: a 1000-pound guinea pig for study of the ovulatory follicular wave in women.</a> Theriogenology. 77 (5), 818-828 (2012).</li><li>Chiang, T., Duncan, F. E., Schindler, K., Schultz, R. M., Lampson, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+that+weakened+centromere+cohesion+is+a+leading+cause+of+age-related+aneuploidy+in+oocytes.">Evidence that weakened centromere cohesion is a leading cause of age-related aneuploidy in oocytes.</a> Curr Biol. 20 (17), 1522-1528 (2010).</li><li>Duncan, F. E., Chiang, T., Schultz, R. M., Lampson, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+that+a+defective+spindle+assembly+checkpoint+is+not+the+primary+cause+of+maternal+age-associated+aneuploidy+in+mouse+eggs.">Evidence that a defective spindle assembly checkpoint is not the primary cause of maternal age-associated aneuploidy in mouse eggs.</a> Biol Reprod. 81 (4), 768-776 (2009).</li><li>Larionov, A., Krause, A., Miller, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+standard+curve+based+method+for+relative+real+time+PCR+data+processing.">A standard curve based method for relative real time PCR data processing.</a> BMC Bioinformatics. 6 (62), (2005).</li><li>Choi, Y. H., Hochi, S., Braun, J., Sato, K., Oguri, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+maturation+of+equine+oocytes+collected+by+follicle+aspiration+and+by+the+slicing+of+ovaries.">In vitro maturation of equine oocytes collected by follicle aspiration and by the slicing of ovaries.</a> Theriogenology. 40 (5), 959-966 (1993).</li><li>Hassold, T., Hunt, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=To+err+(meiotically)+is+human:+the+genesis+of+human+aneuploidy.">To err (meiotically) is human: the genesis of human aneuploidy.</a> Nat Rev Genet. 2 (4), 280-291 (2001).</li><li>Akiyama, T., Nagata, M., Aoki, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inadequate+histone+deacetylation+during+oocyte+meiosis+causes+aneuploidy+and+embryo+death+in+mice.">Inadequate histone deacetylation during oocyte meiosis causes aneuploidy and embryo death in mice.</a> Proc Natl Acad Sci U S A. 103 (19), 7339-7344 (2006).</li><li>Homer, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mad2+prevents+aneuploidy+and+premature+proteolysis+of+cyclin+B+and+securin+during+meiosis+I+in+mouse+oocytes.">Mad2 prevents aneuploidy and premature proteolysis of cyclin B and securin during meiosis I in mouse oocytes.</a> Genes Dev. 19 (2), 202-207 (2005).</li><li>Rambags, B. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+chromosomal+abnormalities+in+equine+embryos+produced+in+vivo+and+in+vitro.">Numerical chromosomal abnormalities in equine embryos produced in vivo and in vitro.</a> Mol Reprod Dev. 72 (1), 77-87 (2005).</li><li>Nabti, I., Marangos, P., Bormann, J., Kudo, N. R., Carroll, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual-mode+regulation+of+the+APC/C+by+CDK1+and+MAPK+controls+meiosis+I+progression+and+fidelity.">Dual-mode regulation of the APC/C by CDK1 and MAPK controls meiosis I progression and fidelity.</a> J Cell Biol. 204 (6), 891-900 (2014).</li><li>Shomper, M., Lappa, C., FitzHarris, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetochore+microtubule+establishment+is+defective+in+oocytes+from+aged+mice.">Kinetochore microtubule establishment is defective in oocytes from aged mice.</a> Cell Cycle. 13 (7), 1171-1179 (2014).</li><li>Luzzo, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+fat+diet+induced+developmental+defects+in+the+mouse:+oocyte+meiotic+aneuploidy+and+fetal+growth+retardation/brain+defects.">High fat diet induced developmental defects in the mouse: oocyte meiotic aneuploidy and fetal growth retardation/brain defects.</a> PLoS One. 7 (11), e49217 (2012).</li><li>Ma, P., Schultz, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+deacetylase+2+(HDAC2)+regulates+chromosome+segregation+and+kinetochore+function+via+H4K16+deacetylation+during+oocyte+maturation+in+mouse.">Histone deacetylase 2 (HDAC2) regulates chromosome segregation and kinetochore function via H4K16 deacetylation during oocyte maturation in mouse.</a> PLoS Genet. 9 (3), e1003377 (2013).</li><li>Yang, F., Baumann, C., Viveiros, M. M., De La Fuente, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+hyperacetylation+during+meiosis+interferes+with+large-scale+chromatin+remodeling,+axial+chromatid+condensation+and+sister+chromatid+separation+in+the+mammalian+oocyte.">Histone hyperacetylation during meiosis interferes with large-scale chromatin remodeling, axial chromatid condensation and sister chromatid separation in the mammalian oocyte.</a> Int J Dev Biol. 56 (10-12), 889-899 (2012).</li><li>Luciano, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oocytes+isolated+from+dairy+cows+with+reduced+ovarian+reserve+have+a+high+frequency+of+aneuploidy+and+alterations+in+the+localization+of+progesterone+receptor+membrane+component+1+and+aurora+kinase+B.">Oocytes isolated from dairy cows with reduced ovarian reserve have a high frequency of aneuploidy and alterations in the localization of progesterone receptor membrane component 1 and aurora kinase B.</a> Biol Reprod. 88 (3), 58 (2013).</li><li>Luciano, A. M., Lodde, V., Franciosi, F., Ceciliani, F., Peluso, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progesterone+receptor+membrane+component+1+expression+and+putative+function+in+bovine+oocyte+maturation,+fertilization,+and+early+embryonic+development.">Progesterone receptor membrane component 1 expression and putative function in bovine oocyte maturation, fertilization, and early embryonic development.</a> Reproduction. 140 (5), 663-672 (2010).</li><li>Terzaghi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PGRMC1+participates+in+late+events+of+bovine+granulosa+cells+mitosis+and+oocyte+meiosis.">PGRMC1 participates in late events of bovine granulosa cells mitosis and oocyte meiosis.</a> Cell Cycle. , 1-14 (2016).</li><li>Susor, A., Jansova, D., Anger, M., Kubelka, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translation+in+the+mammalian+oocyte+in+space+and+time.">Translation in the mammalian oocyte in space and time.</a> Cell Tissue Res. 363 (1), 69-84 (2016).</li><li>Chen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+translation+reveals+a+critical+role+for+deleted+in+azoospermia-like+(Dazl)+at+the+oocyte-to-zygote+transition.">Genome-wide analysis of translation reveals a critical role for deleted in azoospermia-like (Dazl) at the oocyte-to-zygote transition.</a> Genes Dev. 25 (7), 755-766 (2011).</li><li>Ma, J., Flemr, M., Strnad, H., Svoboda, P., Schultz, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maternally+recruited+DCP1A+and+DCP2+contribute+to+messenger+RNA+degradation+during+oocyte+maturation+and+genome+activation+in+mouse.">Maternally recruited DCP1A and DCP2 contribute to messenger RNA degradation during oocyte maturation and genome activation in mouse.</a> Biol Reprod. 88 (1), 11 (2013).</li></ol>

Even though IVM has been performed in horses for more than 20 years16, we do not yet know whether the oocyte can be the origin of embryonic aneuploidy, as has been proposed for humans17. The reason is probably that the preparation of oocyte spreads for chromosome counting results in considerable sample loss. With this in mind, a survey of the methods used for investigating errors in chromosome segregation was conducted to search for the most appropriate technique to apply t...

A vast array of assisted reproduction techniques has been developed to treat infertility in women, companion animals, and endangered species. One of the most common procedures in clinical settings is the retrieval of metaphase II (MII)-stage oocytes from the ovarian follicles by ultrasound-guided transvaginal aspiration, ovum pick-up (OPU)1. These oocytes are then fertilized in vitro (IVF), with the resulting embryo(s) implanted in a recipient uterus. The MII-stage (mature) oocytes are retrieved following the administration of exogenous gonadotropins. However, this treatment is associated, in some patients, with the development of ovarian hyperstimulation syndrome (OHSS)2.
Taking advantage of the intrinsic ability of fully-grown, immature oocytes (GV-stage) to spontaneously resume meiosis once isolated from their follicles, it is possible to obtain mature oocytes without administering gonadotropin3. This procedure is called oocyte in vitro maturation (IVM) and represents a less drug-oriented, less expensive, and more patient-friendly approach to assisted reproductive technology. However, the success of embryo development with in vitro-matured oocytes is generally lower than with in vivo matured oocytes4,5. A possible explanation is that in vitro matured oocytes are more affected by errors in chromosome segregation, and the resulting aneuploidy impairs normal embryonic development6.
Understanding the molecular basis of chromosomal mis-segregation during IVM would ultimately disclose the full potential of this technique. In this vein, the experimental approach used to investigate the morphological and biochemical features of in vitro-matured oocytes, compared to in vivo matured oocytes is here described7,8. Specifically, the procedures for the OPU of immature and mature oocytes and the IVM of immature oocytes are illustrated using adult and naturally-cycling horses as an experimental model. Then, immunofluorescence and image analysis are used to investigate chromosome segregation, spindle morphology, and the global pattern of histone acetylation on these gametes. Finally, a protocol of reverse-transcription and quantitative PCR is described for the analysis of mRNA expression.
Compared with rodent animal models, horses do not allow genetic manipulation, are less easy to manipulate, and require expensive maintenance. However, this model is gaining considerable interest for the study of oocyte maturation9,10 due to the similarity to human ovarian physiology11,12. Moreover, the development of reliable protocols of IVM-IVF in the horse has a substantial economic interest, as it would allow for an increase in the number of foals from mares of high genetic value.
One of the limitations of performing experiments on oocytes, especially in monovulatory species, is the restricted sample availability. This limit has been overcome here by adjusting an approach, previously developed in mice, to horse oocytes13,14 in order to conduct chromosome counting that minimizes the sample loss (see the discussion for a comparison with other available techniques). Moreover, a triple-fluorescence staining protocol has been optimized to conduct multiple analyses on the same sample, and q-PCR analyses were performed on pools of 2 oocytes only.
Overall, the present study describes an experimental approach aimed to morphologically and biochemically characterize the horse oocyte, a cell type that is extremely challenging to study due to the low sample availability. However, it can expand our knowledge of the reproductive biology and infertility of monovulatory species.

<table border="0" cellpadding="0" cellspacing="0" width="802">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:369px;">ultrasound probe</td>
			<td style="width:159px;">Aloka</td>
			<td style="width:113px;">UST-5820-7,5</td>
			<td style="width:161px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">human chorionic gonadotrophin&#160;</td>
			<td>centravet</td>
			<td>CHO004</td>
			<td>1500unit/animal IV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">detomidine</td>
			<td>centravet</td>
			<td>MED010</td>
			<td>9-15&#181;g/kg IV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">butylscopolamine bromure&#160;</td>
			<td>centravet</td>
			<td>EST001</td>
			<td>0,2mg/kg IV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">stereomicroscope</td>
			<td style="width:159px;">NIKON</td>
			<td style="width:113px;">SMZ-2B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">butorphanol</td>
			<td>centravet</td>
			<td>DOL003</td>
			<td>10&#181;g/kg IV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">benzyl-penicillin</td>
			<td>centravet</td>
			<td>DEP203 IM</td>
			<td>15000UI/animal</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TCM199</td>
			<td>Sigma-Aldrich</td>
			<td>M3769 10X1L</td>
			<td>powder for hepes-buffered TCM199</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hepes sodium salt</td>
			<td>Sigma-Aldrich</td>
			<td>H3784-100G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A8806</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">heparin&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>H3149-10KU</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">NaHCO3-buffered TCM199</td>
			<td>Sigma-Aldrich</td>
			<td>M2154-500ML</td>
			<td>liquid for IVM medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">epidermal growth factor</td>
			<td>Sigma-Aldrich</td>
			<td>E4127</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">newborn calf serum</td>
			<td>Sigma-Aldrich</td>
			<td>N4762-500ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-well dishes</td>
			<td>NUNCLON</td>
			<td>144444</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">incubator</td>
			<td>Heraeus</td>
			<td>BB6060</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">monastrol</td>
			<td>Sigma-Aldrich</td>
			<td>M8515</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">hyaluronidase</td>
			<td>Sigma-Aldrich</td>
			<td>H3506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">pronase</td>
			<td>Sigma-Aldrich</td>
			<td>P5147</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">polyvinyl alcohol</td>
			<td>Sigma-Aldrich</td>
			<td>341584</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">triton-X 100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">normal donkey serum&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>D9663</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">rabbit anti-Aurora B phospho-Thr232&#160;</td>
			<td>BioLegend</td>
			<td>636102</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TRITC-conjugated donkey anti-rabbit IgG&#160;</td>
			<td>Vector Laboratories</td>
			<td>711-025-152</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vecta-Shield</td>
			<td>Vector Laboratories</td>
			<td>H-1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">YOPRO1</td>
			<td>Thermofisher Scientific</td>
			<td>Y3603</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">confocal laser scanning microscope&#160;</td>
			<td>LSM 780&#160;</td>
			<td>Zeiss</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">confocal laser scanning microscope&#160;</td>
			<td>LSM 700&#160;</td>
			<td>Zeiss</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ImageJ software</td>
			<td colspan="2">rsb.info. nih.gov/ij/download.html&#160;</td>
			<td>free resource</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mouse anti-alpha-tubulin&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>T8203</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">rabbit anti-acH4K16</td>
			<td>Upstate Biotechnology</td>
			<td>07-329</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">AlexaFluor 488-coniugated donkey anti-mouse IgG</td>
			<td>Life Technologies</td>
			<td>A21202</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4&#8217;,6-diamidino-2-phenylindole&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>D8417</td>
			<td>DAPI</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">centrifuge</td>
			<td>Eppendorf</td>
			<td>5417R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RNALater</td>
			<td>Invitrogen</td>
			<td>AM7020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Luciferase RNA</td>
			<td>Promega</td>
			<td>L4561</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PicoPure RNA Isolation Kit&#160;</td>
			<td>Applied Biosystems</td>
			<td>12204-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">random hexamers&#160;</td>
			<td>Thermofisher Scientific</td>
			<td>N8080127</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mouse Moloney leukaemia virus reverse transcriptase</td>
			<td>Thermofisher Scientific</td>
			<td>28025013</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SYBR green supermix&#160;</td>
			<td>BioRad</td>
			<td>1708880</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">specific primers</td>
			<td>Sigma-Aldrich</td>
			<td></td>
			<td>specific primers were designed using Primer3Plus software (free resource)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">thermal-cycler&#160;</td>
			<td>BioRad</td>
			<td>MyiQ&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mouse monoclonal anti-CENPA</td>
			<td>Abcam</td>
			<td>ab13939</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mouse monoclonal anti-Aurora B</td>
			<td>Abcam</td>
			<td>ab3609</td>
			<td></td>
		</tr>
	</tbody>
</table>

analysis of chromosome segregation, histone acetylation, and spindle morphology in horse oocytes

The field of assisted reproduction has been developed to treat infertility in women, companion animals, and endangered species. In the horse, assisted reproduction also allows for the production of embryos from high performers without interrupting their sports career and contributes to an increase in the number of foals from mares of high genetic value. The present manuscript describes the procedures used for collecting immature and mature oocytes from horse ovaries using ovum pick-up (OPU). These oocytes were then used to investigate the incidence of aneuploidy by adapting a protocol previously developed in mice. Specifically, the chromosomes and the centromeres of metaphase II (MII) oocytes were fluorescently labeled and counted on sequential focal plans after confocal laser microscope scanning. This analysis revealed a higher incidence in the aneuploidy rate when immature oocytes were collected from the follicles and matured in vitro compared to in vivo. Immunostaining for tubulin and the acetylated form of histone four at specific lysine residues also revealed differences in the morphology of the meiotic spindle and in the global pattern of histone acetylation. Finally, the expression of mRNAs coding for histone deacetylases (HDACs) and acetyl-transferases (HATs) was investigated by reverse transcription and quantitative-PCR (q-PCR). No differences in the relative expression of transcripts were observed between in vitro and in vivo matured oocytes. In agreement with a general silencing of the transcriptional activity during oocyte maturation, the analysis of the total transcript amount can only reveal mRNA stability or degradation. Therefore, these findings indicate that other translational and post-translational regulations might be affected.
Overall, the present study describes an experimental approach to morphologically and biochemically characterize the horse oocyte, a cell type that is extremely challenging to study due to low sample availability. However, it can expand our knowledge on the reproductive biology and infertility in monovulatory species.

The original findings of these experiments were described in depth previously7 and are reported herein as an example of results that can be obtained using the described protocols.
Maturation rate
Of the 32 COCs retrieved by OPU from dominant follicles, 28 (88%) were at the MII stage. Fourteen of the 58 COCs collected from follicles 5-25 mm in size ...

Watch this Scientific Journal Video about Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes at JoVE.com

Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes

This manuscript describes an experimental approach to morphologically and biochemically characterize horse oocytes. Specifically, the present work illustrates how to collect immature and mature horse oocytes by ultrasound-guided ovum pick-up (OPU) and how to investigate chromosome segregation, spindle morphology, global histone acetylation, and mRNA expression.

The field of assisted reproduction has been developed to treat infertility in women, companion animals, and endangered species. In the horse, assisted ...

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