Name: fabrication of myogenic engineered tissue constructs
Uploaded: 2009-05-01T00:00:00
Description: Watch this Scientific Journal Video about Fabrication of Myogenic Engineered Tissue Constructs at JoVE.com

Questo lavoro è sostenuto da borse di ricerca dal National Institutes of Health (HL068915; HL088206), un premio Ricercatore Nuovo dal Fondo di ricerca Thrasher, e contributi al fondo di conduzione cardiaca presso il Children Hospital di Boston.

Parte 1: Assemblare costruire stampi <ol><li> Utilizzare una lama di rasoio di dimezzare tubi in silicone (VWR) e tagliarla in 3 pezzi cm di lunghezza. </li><li> Mettere una goccia di protesi in silicone RTV di qualità adesiva (Rhodia) all&#39;interno di ciascuna estremità del tubo. </li><li> Rapidamente posto un piccolo pezzo (1 cm x 1 cm) di poliestere mesh (McMaster-Carr) sulla caduta di silicone e allinearlo con l&#39;estremità del tubo. Questo presenta una superficie leggermente rialzato e piano per il fissagg...

<ol>
	<li>Choi, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+conduction+through+engineered+tissue.">Cardiac conduction through engineered tissue.</a> Am J Pathol. 169 (1), 72-85 (2006).</li><li>Rando, T. A., Blau, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+mouse+myoblast+purification,+characterization,+and+transplantation+for+cell-mediated+gene+therapy.">Primary mouse myoblast purification, characterization, and transplantation for cell-mediated gene therapy.</a> J Cell Biol. 125 (6), 1275-1287 (1994).</li><li>Blau, H. M., Webster, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+human+muscle+cells.">Isolation and characterization of human muscle cells.</a> Proc Natl Acad Sci U S A. 78 (9), 5623-5627 (1981).</li><li>Powell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-engineered+human+bioartificial+muscles+expressing+a+foreign+recombinant+protein+for+gene+therapy.">Tissue-engineered human bioartificial muscles expressing a foreign recombinant protein for gene therapy.</a> Hum Gene Ther. 10 (4), 565-577 (1999).</li><li>Vandenburgh, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-engineered+skeletal+muscle+organoids+for+reversible+gene+therapy.">Tissue-engineered skeletal muscle organoids for reversible gene therapy.</a> Hum Gene Ther. 7 (17), 2195-2200 (1996).</li><li>Gallop, P. M., Seifter, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Properties+of+Soluble+Collagens.">Preparation and Properties of Soluble Collagens.</a> Methods in Enzymology. 6, 635-641 (1963).</li></ol>

Le forme in cui il costrutto tessuto sarà cast può essere effettuato in qualsiasi forma e dimensione, ma ci deve essere almeno due punti di attacco. In caso contrario, la matrice e le cellule formano una struttura sferica e le cellule muoiono. Nel presente protocollo, si descrive l&#39;utilizzo di una maglia in poliestere per questo scopo, ma abbiamo anche utilizzato con successo in rete in acciaio inox. Ovviamente, più grandi stampi richiederà più celle e un volume maggiore di altri ingredienti. Quando si effettua...

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		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Silicone tubing</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>60985-724</td>
<td>&nbsp;</td>
<tr>
<td>Silicone adhesive</td>
<td>&nbsp;</td>
<td>Rhodia Silicones</td>
<td>MED ADH 4300 RTV</td>
<td>&nbsp;</td>
<tr>
<td>Polyester Mesh</td>
<td>&nbsp;</td>
<td>McMaster-Carr</td>
<td>93185T17</td>
<td>&nbsp;</td>
<tr>
<td>Laminin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>L2020</td>
<td>&nbsp;</td>
<tr>
<td>Nutrient Mixture F-10 HAM</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>N6908</td>
<td>&nbsp;</td>
<tr>
<td>Fetal Bovine Serum</td>
<td>&nbsp;</td>
<td>Atlanta Biologicals</td>
<td>S11550</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin/Streptomycin</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15140</td>
<td>&nbsp;</td>
<tr>
<td>Fungizone</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15290-018</td>
<td>&nbsp;</td>
<tr>
<td>Dispase-2</td>
<td>&nbsp;</td>
<td>Roche</td>
<td>10295825001</td>
<td>&nbsp;</td>
<tr>
<td>Collagenase 2</td>
<td>&nbsp;</td>
<td>Worthington</td>
<td>46H8863</td>
<td>&nbsp;</td>
<tr>
<td>Basic Fibroblast Growth Factor</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>G5071</td>
<td>&nbsp;</td>
<tr>
<td>150 mm tissue culture dishes</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>353025</td>
<td>&nbsp;</td>
<tr>
<td>0.05% (1X) Trypsin-EDTA</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>25300</td>
<td>&nbsp;</td>
<tr>
<td>1X Hanks Balanced Salt Solution</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>14170-112</td>
<td>&nbsp;</td>
<tr>
<td>7.5% NaHCO3</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>25080-094</td>
<td>&nbsp;</td>
<tr>
<td>70 &mu;m cell strainer</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352350</td>
<td>&nbsp;</td>
<tr>
<td>6-well plates</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>353046</td>
<td>&nbsp;</td>
<tr>
<td>50 mL Conical Vial</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352098</td>
<td>&nbsp;</td>
<tr>
<td>15 mL Conical Vial</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352099</td>
<td>&nbsp;</td>
<tr>
<td>0.2 &mu;m filter</td>
<td>&nbsp;</td>
<td>Nalgene</td>
<td>194-2520</td>
<td>&nbsp;</td>		</tbody>
		</table>
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fabrication of myogenic engineered tissue constructs

Nonostante il fatto che i pacemaker elettronici sono salvavita dispositivi medici, le loro prestazioni a lungo termine nei pazienti pediatrici può essere problematico a causa delle restrizioni imposte dalle ridotte dimensioni di un bambino e la loro crescita inevitabile. Di conseguenza, vi è una reale necessità di terapie innovative progettate specificamente per i pazienti pediatrici con disturbi del ritmo cardiaco. Proponiamo che una alternativa biologica conduttivo costituito da una matrice a base di collagene contenenti autologously cellule derivate potrebbe adattarsi meglio alla crescita, ridurre la necessità di interventi chirurgici ricorrenti, e migliorare notevolmente la qualità della vita per questi pazienti. Nel presente studio, si descrive una procedura per l&#39;integrazione primaria mioblasti scheletrici colture di cellule in una matrice idrogel di moda un costrutto tessuto chirurgicamente impiantabili che servirà come un condotto elettrico tra le camere superiori e inferiori del cuore. In ultima analisi, possiamo anticipare utilizza questo tipo di ingegneria tessutale per ripristinare atrioventricolare di conduzione elettrica nei bambini con arresto cardiaco completo. In considerazione di questo, abbiamo isolare mioblasti dai muscoli scheletrici di ratti neonati Lewis e la piastra di loro su piatti tessuto laminina rivestite cultura utilizzando una versione modificata di protocolli stabiliti<sup&gt; [2, 3]</sup&gt;. Dopo uno o due giorni, cellule coltivate vengono raccolti e mescolati con gli antibiotici, il collagene di tipo 1, Matrigel ™ e NaHCO<sub&gt; 3</sub&gt;. Il risultato è una viscosa, soluzione uniforme che può essere gettato in uno stampo di quasi ogni forma e dimensione<sup&gt; [1, 4, 5]</sup&gt;. Per il nostro tessuto costruisce, ci avvaliamo di collagene di tipo 1 isolato dalla pelle di agnello del feto utilizzando le procedure standard<sup&gt; [6]</sup&gt;. Una volta che il tessuto è solidificato a 37 ° C, la cultura dei media è attentamente aggiunto alla piastra fino a quando il costrutto è sommerso. L&#39;ingegneria tessutale è poi permesso di condensare ulteriormente attraverso la disidratazione per altri 2 giorni, a quel punto è pronto per<em&gt; In vitro</em&gt; Valutazione o chirurgico-impianto.

Watch this Scientific Journal Video about Fabrication of Myogenic Engineered Tissue Constructs at JoVE.com

Fabrication of Myogenic Engineered Tissue Constructs

In questo studio dimostriamo realizzazione di costruzioni a base di collagene dei tessuti, contenenti mioblasti scheletrici. Questi costrutti ingegnerizzati in 3-D possono essere usati per sostituire o riparare i tessuti<em&gt; In vivo</em&gt;. Per i nostri scopi, abbiamo progettato questi come un canale atrioventricolare elettrico per la riparazione di blocco cardiaco completo<sup&gt; [1]</sup&gt;.

Fabbricazione di miogenici Costrutti di ingegneria tessutale

Despite the fact that electronic pacemakers are life-saving medical devices, their long-term performance in pediatric patients can be problematic owing to ...

fabrication-of-myogenic-engineered-tissue-constructs

Research

JoVE Journal

Biology

PDMS Device Fabrication and Surface Modification

PDMS fabbricazione del dispositivo e la modifica della superficie

Ricerca

Biologia

Fabrication of the Thermoplastic Microfluidic Channels

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using polymer/nanoparticle composite microscale lysis and solid phase extraction columns. The recovered samples are concentrated, small volume samples that are PCRable, without any additional cleanup. Here, we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then, we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns. We demonstrate grafting and polymerization of a carbon nanotube/polymer composite column for bacterial cell lysis. We then show the lysis process followed by solid phase extraction of nucleic acids from the sample on chip using a silica/polymer composite column. The attached protocols contain detailed instructions on how to make both lysis and solid phase extraction columns.

Here we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns.

Fabbricazione dei canali termoplastico Microfluidic

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using ...

Actin Co-Sedimentation Assay; for the Analysis of Protein Binding to F-Actin

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates tension and helps maintains cellular shape.  Although the actin cytoskeleton is a rigid structure, it is a dynamic structure that is constantly remodeling.  A number of proteins can bind to the actin cytoskeleton.  The binding of a particular protein to F-actin is often desired to support cell biological observations or to further understand dynamic processes due to remodeling of the actin cytoskeleton. The actin co-sedimentation assay is an in vitro assay routinely used to analyze the binding of specific proteins or protein domains with F-actin.  The basic principles of the assay involve an incubation of the protein of interest (full length or domain of) with F-actin, ultracentrifugation step to pellet F-actin and analysis of the protein co-sedimenting with F-actin.  Actin co-sedimentation assays can be designed accordingly to measure actin binding affinities and in competition assays.

Proteins bind to filamentous actin (F-actin) through distinct actin binding modules. In this video we demonstrate the procedure of actin co-sedimentation, which is an in vitro assay routinely used to analyze proteins or specific domains that bind F-actin.

Actina Co-sedimentazione di analisi, per l&#39;Analisi del Binding Protein a F-Actina

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates ...

Fabrication of Amperometric Electrodes

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we describe the techniques needed to generate low noise (&lt;0.5 pA) electrodes.  The techniques have been modified from published descriptions by previous researchers (1,2).  Electrodes are made by preparing carbon fibers and threading them individually into each capillary tube by using a vacuum with a filter to aspirate the fiber.  Next, the capillary tube with fiber is pulled by an electrode puller, creating two halves, each with a fine-pointed tip.  The electrodes are dipped in hot, liquid epoxy mixed with hardener to create an epoxy-glass seal.  Lastly, the electrodes are placed in an oven to cure the epoxy.  Careful handling of the electrodes is critical to ensure that they are made consistently and without damage.  This protocol shows how to fabricate and cut amperometric electrodes for recording from single cells.

This protocol describes how to generate carbon fiber electrodes. The electrodes are subsequently used to detect catecholamine release from vesicles with carbon fiber amperometry.

Fabbricazione di elettrodi amperometrici

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we ...

Implantation of Engineered Tissue in the Rat Heart

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in common laboratory rats or mice and these quite frequently serve as an intermediate step between bench-top experiments and large animal testing or human trials. Given that rodents provide an established, cost-effective, and physiologically-relevant model system in which to test novel combinations of scaffolding materials and cells, they are particularly well-suited for cardiovascular tissue engineering studies. Presently, we describe an open-heart surgical procedure to implant engineered tissue containing myogenic progenitor cells in the atrioventricular (AV) groove of a rat heart. These implants are intended to create an electrical conduit between the right atrium and right ventricle with the ultimate goal of providing an alternative treatment to conventional pacemaker implantation in pediatric patients with complete heart block[1]. The engineered tissue is implanted in the AV-groove by means of a thoracotomy. For our purposes, Lewis rats are anesthetized and invasively ventilated to maintain positive airway pressure during the sterile surgical procedure. The approach to the heart is performed by a right thoracotomy through an antero-lateral incision at the 5th intercostal space. The tissue construct is fixed in the AV groove using a single 7-0 Prolene suture and positioned between the right ventricle and atrium at the ventral portion of the heart. The epicardium is partially removed to allow direct contact between the recipient myocardial cells and those contained in the engineered tissue. Following implantation, the chest wall is closed in layers, any pneumothorax is evacuated, and the animal is extubated and treated with analgesic.

Here, we describe a cardiac surgical procedure to implant engineered tissue in the atrioventricular (AV)-groove of an adult Lewis rat.

L&#39;impianto di ingegneria tessutale nel Cuore Rat

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in ...

Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster

Gene expression patterns are specified by cis-regulatory element (CRE) sequences, which are also called enhancers or cis-regulatory modules. A typical CRE possesses an arrangement of binding sites for several transcription factor proteins that confer a regulatory logic specifying when, where, and at what level the regulated gene(s) is expressed. The full set of CREs within an animal genome encodes the organism&prime;s program for development1, and empirical as well as theoretical studies indicate that mutations in CREs played a prominent role in morphological evolution2-4. Moreover, human genome wide association studies indicate that genetic variation in CREs contribute substantially to phenotypic variation5,6. Thus, understanding regulatory logic and how mutations affect such logic is a central goal of genetics. 
Reporter transgenes provide a powerful method to study the in vivo function of CREs. Here a known or suspected CRE sequence is coupled to heterologous promoter and coding sequences for a reporter gene encoding an easily observable protein product. When a reporter transgene is inserted into a host organism, the CRE&prime;s activity becomes visible in the form of the encoded reporter protein. P-element mediated transgenesis in the fruit fly species Drosophila (D.) melanogaster7 has been used for decades to introduce reporter transgenes into this model organism, though the genomic placement of transgenes is random. Hence, reporter gene activity is strongly influenced by the local chromatin and gene environment, limiting CRE comparisons to being qualitative. In recent years, the phiC31 based integration system was adapted for use in D. melanogaster to insert transgenes into specific genome landing sites8-10. This capability has made the quantitative measurement of gene and, relevant here, CRE activity11-13 feasible. The production of transgenic fruit flies can be outsourced, including phiC31-based integration, eliminating the need to purchase expensive equipment and/or have proficiency at specialized transgene injection protocols. 
Here, we present a general protocol to quantitatively evaluate a CRE&prime;s activity, and show how this approach can be used to measure the effects of an introduced mutation on a CRE&prime;s activity and to compare the activities of orthologous CREs. Although the examples given are for a CRE active during fruit fly metamorphosis, the approach can be applied to other developmental stages, fruit fly species, or model organisms. Ultimately, a more widespread use of this approach to study CREs should advance an understanding of regulatory logic and how logic can vary and evolve.

Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster

Phenotypic variation for traits can result from mutations in cis-regulatory element (CRE) sequences that control gene expression patterns. Methods derived for use in Drosophila melanogaster can quantitatively compare the levels of spatial and temporal patterns of gene expression mediated by modified or naturally occurring CRE variants.

Confronto quantitativo di Cis-Regulatory Element (CRE) Attività in transgenici Drosophila melanogaster</em

Gene expression patterns are specified by cis-regulatory element (CRE) sequences, which are also called enhancers or cis-regulatory modules. A typical CRE ...

Mouse Sperm Cryopreservation and Recovery using the I&middot;Cryo Kit

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies. Many of these valuable animals exist only as live animals, with no backup plan in case of emergency. Cryopreservation of embryos can provide this backup, but is costly, can be a lengthy procedure, and generally requires a large number of animals for success. Since the discovery that mouse sperm can be successfully cryopreserved with a basic cryoprotective agent (CPA) consisting of 18&#37; raffinose and 3&#37; skim milk, sperm cryopreservation has become an acceptable and cost-effective procedure for archiving, distributing and recovery of these valuable strains.
 Here we demonstrate a newly developed I&bull;Cryo kit for mouse sperm cryopreservation. Sperm from five commonly-used strains of inbred mice were frozen using this kit and then recovered. Higher protection ratios of sperm motility (&gt; 60&#37;) and rapid progressive motility (&gt; 45&#37;) compared to the control (basic CPA) were seen for sperm frozen with this kit in 5 inbred mouse strains. Two cell stage embryo development after IVF with the recovered sperm was improved consistently in all 5 mouse strains examined. Over a 1.5 year period, 49 GM mouse lines were archived by sperm cryopreservation with the I&bull;Cryo kit and later recovered by IVF.

Mouse Sperm Cryopreservation and Recovery using the I&amp;middot;Cryo Kit

Here we demonstrate the newly developed I&#x2022;Cryo kit for mouse sperm cryopreservation. Two-cell stage embryo development with frozen-thawed sperm was improved consistently in 5 mouse strains with the use of this kit. Over a 1.5 year period, 49 genetically modified mouse lines were archived by sperm cryopreservation with the I&#x2022;Cryo kit and later successfully recovered by IVF.

Crioconservazione del mouse Sperm and Recovery utilizzando il Kit · I Cryo

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies.  Many of these ...

Fabrication and Use of MicroEnvironment microArrays (MEArrays)

The interactions between cells and their surrounding microenvironment have functional consequences for cellular behaviour. On the single cell level, distinct microenvironments can impose differentiation, migration, and proliferation phenotypes, and on the tissue level the microenvironment processes as complex as morphogenesis and tumorigenesis1. Not only do the cell and molecular contents of microenvironments impact the cells within, but so do the elasticity2 and geometry3 of the tissue. Defined as the sum total of cell-cell, -ECM, and -soluble factor interactions, in addition to physical characteristics, the microenvironment is complex. The phenotypes of cells within a tissue are partially due to their genomic content and partially due to the combinatorial interactions with the microenviroment. A major challenge is to link specific combinations of microenvironmental components with distinctive behaviours.
Here, we present the microenvironment microarray (MEArray) platform for cell-based functional screening of interactions with combinatorial microenvironments4. The method allows for simultaneous control of the molecular composition and the elastic modulus, and combines the use of widely available microarray and micropatterning technologies. MEArray screens require as few as 10,000 cells per array, which facilitates functional studies of rare cell types such as adult progenitor cells. A limitation of the technology is that entire tissue microenvironments cannot be completely recapitulated on MEArrays. However, comparison of responses in the same cell type to numerous related microenvironments, for instance pairwise combinations of ECM proteins that characterize a given tissue, will provide insights into how microenvironmental components elicit tissue-specific functional phenotypes.
MEArrays can be printed using a wide variety of recombinant growth factors, cytokines, and purified ECM proteins, and combinations thereof. The platform is limited only by the availability of specific reagents. MEArrays are amenable to time-lapsed analysis, but most often are used for end point analyses of cellular functions that are measureable with fluorescent probes. For instance, DNA synthesis, apoptosis, acquisition of differentiated states, or production of specific gene products are commonly measured. Briefly, the basic flow of an MEArray experiment is to prepare slides coated with printing substrata and to prepare the master plate of proteins that are to be printed. Then the arrays are printed with a microarray robot, cells are allowed to attach, grow in culture, and then are chemically fixed upon reaching the experimental endpoint. Fluorescent or colorimetric assays, imaged with traditional microscopes or microarray scanners, are used to reveal relevant molecular and cellular phenotypes (Figure 1).

Fabrication and Use of MicroEnvironment microArrays MEArrays

A combinatorial functional screening method for gaining insights into the impacts of the molecular composition of microenvironments on cellular functions is described. The method takes advantage of existing microarray-based technologies to generate arrays of defined combinatorial microenvironments that support cell adhesion and functional analysis.

Realizzazione e utilizzo di microarrays microambiente (MEArrays)

The interactions between cells and their surrounding microenvironment have functional consequences for cellular behaviour. On the single cell level, ...

Recombineering Homologous Recombination Constructs in Drosophila

The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a genetic model organism for human-disease related research. Recent years have seen technical advancements like homologous recombination and recombineering. However, generating unequivocal null mutations or tagging endogenous proteins remains a substantial effort for most genes. Here, we describe and demonstrate techniques for using recombineering-based cloning methods to generate vectors that can be used to target and manipulate endogenous loci in vivo. Specifically, we have established a combination of three technologies: (1) BAC transgenesis/recombineering, (2) ends-out homologous recombination and (3) Gateway technology to provide a robust, efficient and flexible method for manipulating endogenous genomic loci. In this protocol, we provide step-by-step details about how to (1) design individual vectors, (2) how to clone large fragments of genomic DNA into the homologous recombination vector using gap repair, and (3) how to replace or tag genes of interest within these vectors using a second round of recombineering. Finally, we will also provide a protocol for how to mobilize these cassettes in vivo to generate a knockout, or a tagged gene via knock-in. These methods can easily be adopted for multiple targets in parallel and provide a means for manipulating the Drosophila genome in a timely and efficient manner.

Recombineering Homologous Recombination Constructs in Drosophila

Homologous recombination techniques greatly advance Drosophila genetics by enabling the creation of molecularly precise mutations. The recent adoption of recombineering allows one to manipulate large pieces of DNA and transform them into Drosophila6. The methods presented here combine these techniques to rapidly generate large homologous recombination vectors.

Recombineering costrutti omologhi ricombinazione<em&gt; Drosophila</em

The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a ...

Preparation of Primary Myogenic Precursor Cell/Myoblast Cultures from Basal Vertebrate Lineages

Due to the inherent difficulty and time involved with studying the myogenic program in vivo, primary culture systems derived from the resident adult stem cells of skeletal muscle, the myogenic precursor cells (MPCs), have proven indispensible to our understanding of mammalian skeletal muscle development and growth. Particularly among the basal taxa of Vertebrata, however, data are limited describing the molecular mechanisms controlling the self-renewal, proliferation, and differentiation of MPCs. Of particular interest are potential mechanisms that underlie the ability of basal vertebrates to undergo considerable postlarval skeletal myofiber hyperplasia (i.e.&#160;teleost fish) and full regeneration following appendage loss (i.e.&#160;urodele amphibians). Additionally, the use of cultured myoblasts could aid in the understanding of regeneration and the recapitulation of the myogenic program and the differences between them. To this end, we describe in detail a robust and efficient protocol (and variations therein) for isolating and maintaining MPCs and their progeny, myoblasts and immature myotubes, in cell culture as a platform for understanding the evolution of the myogenic program, beginning with the more basal vertebrates. Capitalizing on the model organism status of the zebrafish (Danio rerio), we report on the application of this protocol to small fishes of the cyprinid clade Danioninae. In tandem, this protocol can be utilized to realize a broader comparative approach by isolating MPCs from the Mexican axolotl (Ambystomamexicanum) and even laboratory rodents. This protocol is now widely used in studying myogenesis in several fish species, including rainbow trout, salmon, and sea bream1-4.

In vitro culture systems have proven indispensible to our understanding of vertebrate myogenesis. However, much remains to be learned about nonmammalian skeletal muscle development and growth, particularly in basal taxa. An efficient and robust protocol for isolating the adult stem cells of this tissue, the myogenic precursor cells (MPCs), and maintaining their self-renewal, proliferation, and differentiation in a primary culture setting allows for the identification of conserved and divergent regulatory mechanisms throughout the vertebrate lineages.

Preparazione di primaria Miogenica precursori cellulari / Culture mioblasti dal basale vertebrati Lignaggi

Due to the inherent difficulty and time involved with studying the myogenic program in vivo, primary culture systems derived from the resident adult stem ...