Name: in vivo imaging of transgenic gene expression in individual retinal progenitors in chimeric zebrafish embryos to study cell nonautonomous influences
Uploaded: 2017-03-22T15:00:00
Description: Watch this Scientific Journal Video about In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences at JoVE.c

This work was supported by an ARC DECRA to PRJ (DE120101311) and by a Deutsche Forschungsgemeinschaft (DFG) research grant to LP (PO 1440/1-1). The Australian Regenerative Medicine Institute is supported by funds from the State Government of Victoria and the Australian Federal Government. We acknowledge Dr Jeremy Ng Chi Kei, who conducted experiments described here as published in Kei et al., 2016. We are grateful for provisions of transgenic fish from Prof. Higashijima and thank Profs. Turner and Rupp for the provision of the pCS2+ plasmid and Dr. Wilkinson for generating H2B-RFP and H2A-GFP constructs. We thank FishCore facility staff (Monash University) for taking care of our animals.

All procedures were carried out according to the provisions of the Australian National Health and Medical Research Council code of practice for the care and use of animals and were approved by the institutional ethics committees.
1. Preparation of Zebrafish
<ol>
	<li>Adult fish pairing
	<ol>
		<li>Set up adult fish as pairs (or two pairs) in appropriately sized breeding tanks the evening prior to use.</li>
		<li>To keep the female separated from the male, use a divider to enable the fish to ...

<ol>
	<li>Lieschke, G. J., Currie, 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=Animal+models+of+human+disease:+zebrafish+swim+into+view.">Animal models of human disease: zebrafish swim into view.</a> Nat Rev Genet. 8, 353-367 (2007).</li><li>Scholpp, S., Poggi, L., Zigman, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+on+the+stage+-+spotlight+on+nervous+system+development+in+zebrafish:+EMBO+practical+course,+KIT,+Sept.+2013.">Brain on the stage - spotlight on nervous system development in zebrafish: EMBO practical course, KIT, Sept. 2013.</a> Neural Dev. 8, 23 (2013).</li><li>Cayouette, M., Poggi, L., Harris, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lineage+in+the+vertebrate+retina.">Lineage in the vertebrate retina.</a> Trends Neurosci. 29, 563-570 (2006).</li><li>Poggi, L., Vitorino, M., Masai, I., Harris, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influences+on+neural+lineage+and+mode+of+division+in+the+zebrafish+retina+in+vivo.">Influences on neural lineage and mode of division in the zebrafish retina in vivo.</a> J Cell Biol. 171, 991-999 (2005).</li><li>Poggi, L., Zolessi, F. R., Harris, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-lapse+analysis+of+retinal+differentiation.">Time-lapse analysis of retinal differentiation.</a> Curr Opin Cell Biol. 17, 676-681 (2005).</li><li>Jusuf, P. R., 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=Biasing+amacrine+subtypes+in+the+Atoh7+lineage+through+expression+of+Barhl2.">Biasing amacrine subtypes in the Atoh7 lineage through expression of Barhl2.</a> J Neurosci. 32, 13929-13944 (2012).</li><li>Jusuf, P. R., 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=Origin+and+determination+of+inhibitory+cell+lineages+in+the+vertebrate+retina.">Origin and determination of inhibitory cell lineages in the vertebrate retina.</a> J Neurosci. 31, 2549-2562 (2011).</li><li>Jusuf, P., Harris, W. A., Poggi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+retinal+progenitor+lineages+in+developing+zebrafish+embryos.">Imaging retinal progenitor lineages in developing zebrafish embryos.</a> Cold Spring Harb Protoc. 2013, (2013).</li><li>Jusuf, P., Harris, W. A., Poggi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+transgenic+zebrafish+embryos+for+imaging+the+developing+retina.">Preparation of transgenic zebrafish embryos for imaging the developing retina.</a> Cold Spring Harb Protoc. 2013, (2013).</li><li>Vitorino, 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=Vsx2+in+the+zebrafish+retina:+restricted+lineages+through+derepression.">Vsx2 in the zebrafish retina: restricted lineages through derepression.</a> Neural Dev. 4, 14 (2009).</li><li>Reh, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-specific+regulation+of+neuronal+production+in+the+larval+frog+retina.">Cell-specific regulation of neuronal production in the larval frog retina.</a> J Neurosci. 7, 3317-3324 (1987).</li><li>Reh, T. A., Tully, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+tyrosine+hydroxylase-containing+amacrine+cell+number+in+larval+frog+retina.">Regulation of tyrosine hydroxylase-containing amacrine cell number in larval frog retina.</a> Dev Biol. 114, 463-469 (1986).</li><li>Livesey, F. J., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertebrate+neural+cell-fate+determination:+lessons+from+the+retina.">Vertebrate neural cell-fate determination: lessons from the retina.</a> Nature reviews. Neuroscience. 2, 109-118 (2001).</li><li>Zolessi, F. R., Poggi, L., Wilkinson, C. J., Chien, C. B., Harris, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polarization+and+orientation+of+retinal+ganglion+cells+in+vivo.">Polarization and orientation of retinal ganglion cells in vivo.</a> Neural Dev. 1, 2 (2006).</li><li>Kimura, Y., Okamura, Y., Higashijima, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=alx,+a+zebrafish+homolog+of+Chx10,+marks+ipsilateral+descending+excitatory+interneurons+that+participate+in+the+regulation+of+spinal+locomotor+circuits.">alx, a zebrafish homolog of Chx10, marks ipsilateral descending excitatory interneurons that participate in the regulation of spinal locomotor circuits.</a> J Neurosci. 26, 5684-5697 (2006).</li><li>Kimura, Y., Satou, C., Higashijima, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=V2a+and+V2b+neurons+are+generated+by+the+final+divisions+of+pair-producing+progenitors+in+the+zebrafish+spinal+cord.">V2a and V2b neurons are generated by the final divisions of pair-producing progenitors in the zebrafish spinal cord.</a> Development. 135, 3001-3005 (2008).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Zebrafish Book: A Guide for the Laboratory Use of Zebrafish (Danio Rerio). , (2007).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev Dyn. 203 (3), 253-310 (1995).</li><li>Kei, J. N., Dudczig, S., Currie, P. D., Jusuf, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feedback+from+each+retinal+neuron+population+drives+expression+of+subsequent+fate+determinant+genes+without+influencing+the+cell+cycle+exit+timing.">Feedback from each retinal neuron population drives expression of subsequent fate determinant genes without influencing the cell cycle exit timing.</a> J Comp Neurol. 524, 2553-2566 (2016).</li><li>Yuan, S., Sun, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+mRNA+and+morpholino+antisense+oligonucleotides+in+zebrafish+embryos.">Microinjection of mRNA and morpholino antisense oligonucleotides in zebrafish embryos.</a> J Vis Exp. , (2009).</li><li>Rosen, J. N., Sweeney, M. F., Mably, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+zebrafish+embryos+to+analyze+gene+function.">Microinjection of zebrafish embryos to analyze gene function.</a> J Vis Exp. , (2009).</li><li>Zou, J., Wei, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+of+GFP-expressing+blastomeres+for+live+imaging+of+retinal+and+brain+development+in+chimeric+zebrafish+embryos.">Transplantation of GFP-expressing blastomeres for live imaging of retinal and brain development in chimeric zebrafish embryos.</a> J Vis Exp. , (2010).</li><li>Kemp, H. A., Carmany-Rampey, A., Moens, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generating+chimeric+zebrafish+embryos+by+transplantation.">Generating chimeric zebrafish embryos by transplantation.</a> J Vis Exp. , (2009).</li><li>Schier, A. F., Talbot, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+genetics+of+axis+formation+in+zebrafish.">Molecular genetics of axis formation in zebrafish.</a> Annu Rev Genet. 39, 561-613 (2005).</li><li>De Luca, E., 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=ZebraBeat:+a+flexible+platform+for+the+analysis+of+the+cardiac+rate+in+zebrafish+embryos.">ZebraBeat: a flexible platform for the analysis of the cardiac rate in zebrafish embryos.</a> Sci Rep. 4, 4898 (2014).</li><li>Lin, J. W., 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=Differential+requirement+for+ptf1a+in+endocrine+and+exocrine+lineages+of+developing+zebrafish+pancreas.">Differential requirement for ptf1a in endocrine and exocrine lineages of developing zebrafish pancreas.</a> Dev Biol. 274, 491-503 (2004).</li><li>Hollyfield, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histogenesis+of+the+retina+in+the+killifish,+Fundulus+heteroclitus.">Histogenesis of the retina in the killifish, Fundulus heteroclitus.</a> J Comp Neurol. 144 (3), 373-380 (1972).</li><li>La Vail, M. M., Rapaport, D. H., Rakic, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytogenesis+in+the+monkey+retina.">Cytogenesis in the monkey retina.</a> J Comp Neurol. 309 (1), 86-114 (1991).</li><li>Rapaport, D. H., Wong, L. L., Wood, E. D., Yasumura, D., LaVail, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Timing+and+topography+of+cell+genesis+in+the+rat+retina.">Timing and topography of cell genesis in the rat retina.</a> J Comp Neurol. 474 (2), 304-324 (2004).</li><li>Sharma, S. C., Ungar, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histogenesis+of+the+goldfish+retina.">Histogenesis of the goldfish retina.</a> J Comp Neurol. 191 (3), 373-382 (1980).</li><li>Stiemke, M. M., Hollyfield, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+birthdays+in+Xenopus+laevis+retina.">Cell birthdays in Xenopus laevis retina.</a> Differentiation. 58 (3), 189-193 (1995).</li></ol>

Understanding the extent to which neighboring cells influence timing of the expression of crucial cell fate determining factors is essential when aiming to efficiently instruct embryonic or induced multipotent stem cells to differentiate into a specific post-mitotic cell type or even patterned tissue. Furthermore, examining these molecular events in the developing cells of the living animal additionally provides relevant dynamic (temporal and spatial) information on the particular cellular contexts associated with these ...

The ability to visualize important developmental processes in an in vivo vertebrate has contributed to making the zebrafish a key model for studying normal and disease conditions (reviewed in 1,2). In particular, the neural retina is an accessible part of the central nervous system. The retina lends itself to easily perform studies of neurogenesis due to its highly organized, yet relatively simple structure, and its highly conserved neuron types across vertebrate species 3. Dynamics of cellular behaviors such as proliferation, cell cycle exit, asymmetric cell division, fate specification, differentiation, and neural circuitry formation can be followed throughout the entire process of retinogenesis, which is completed in the central retina of the zebrafish by 3 d postfertilization (dpf) 4,5,6,7.
Furthermore, the functional requirements of different genes in each of the above mentioned stages can be concomitantly assessed in the zebrafish retina, providing an advantage over other vertebrate models in which phenotypes resulting from application of gene knockout techniques can only be assessed upon post-mortem examination of fixed tissues. In particular, the use of transgenic lines in which we can visualize and monitor the expression of fluorescent proteins as reporter transgenes in the retina, allows us to obtain temporal resolution of gene expression that underlies the genesis of a particular neuronal cell type. Due to the rapid development of zebrafish, these events can be visualized during the entire developmental period, thereby providing deeper insights into the temporal importance of gene expression in relation to neuronal cell identity acquisition and cell behavior.
Finally, these approaches can be combined efficiently in the zebrafish with the generation of chimera via transplantations, resulting in insights into two key aspects of gene function. Firstly, examining cells transplanted from a donor embryo, in which a particular gene was knocked down while they develop in an unlabeled wild type environment, allows us to obtain relevant information about gene function in a cell-autonomous manner. This leads to important insights about the function of retinal fate determinant factors within the progenitor cells they are normally expressed in. This is exemplified by the examination of the developmental fate outcome of progenitors that can no longer generate functional protein from these genes 4,6,8,9. Utilizing this approach, we have shown that many fate determinant factors (e.g., Vsx1, Atoh7, Ptf1a, Barhl2) act cell-autonomously to drive specific retinal neuronal fates; the lack of gene expression primarily leads to a fate switch, such that the cells with gene knockdown remain viable by adopting an alternate cell fate 4,6,7,10. Secondly, such chimeric experiments can be used to assess how wild type progenitors behave when they develop within different genetic environments. For example, by comparing the development of WT cells that usually express a gene of interest (and reporter transgene) in a WT versus manipulated host environment (e.g., gene knockout / knockdown), the resulting effects on gene expression and cell fate can be assessed. The lack of certain neuron types in the host environment, for instance, has been shown to influence wild type progenitor behavior in a cell non-autonomous manner, to bias them towards differentiating into the underrepresented or missing neuron types 4,7,11,12. Given that retinal neurons are born in a conserved histogenic order by the sequentially timed expression of specific neuronal fate determinant genes (fate gene expression) (reviewed in 13), we used these methods to demonstrate how the timing of fate gene expression in wild type progenitors is affected when such progenitors develop in retinal host environments with induced aberrant cellular compositions. Here, we outline these approaches as evidence for how the combination of relatively standard and widely used techniques enables the examination of the timing of fate gene expression in developing retinal progenitors 8,9.
This protocol describes an experimental approach combining time-lapse imaging with the ease of performing transplantation in the ex vivo developing zebrafish embryo to follow individual mosaically labeled cells throughout the entire period of developmental retinogenesis. By performing functional gene manipulations either in the host embryo, donor embryo, both or neither, one can assess the cell autonomy of gene function. This approach can be adapted widely to similar research questions in any other system for which the individual components outlined here are suitable.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Agarose</td>
			<td>Bioline</td>
			<td>BIO-41025</td>
			<td>Agarose coated dishes can be prepared a few days prior, sealed with parafilm to prevent drying and stored at 4C</td>
		</tr>
		<tr>
			<td>Agarose low melt</td>
			<td>Sigma</td>
			<td>A9414-100G</td>
			<td>Can be prepared in larger volume, microwaved to liquify and then kept molte in 40C waterbath. 1 ml aliquots can be prepared (one for each group of embryos mounted).</td>
		</tr>
		<tr>
			<td>borosillicate glass capillary tube w/o filament</td>
			<td>SDR Scientfic</td>
			<td>30-0035</td>
			<td>alternatives with similar diameter can be used&#160;</td>
		</tr>
		<tr>
			<td>borosillicate glass capillary tube with filament</td>
			<td>SDR Scientfic</td>
			<td>30-0038</td>
			<td>alternatives with similar diameter can be used&#160;</td>
		</tr>
		<tr>
			<td>glass petri dishes (60 mm diameter)</td>
			<td>Science Supply</td>
			<td>1070506</td>
			<td>any glass alternative of any size</td>
		</tr>
		<tr>
			<td>Injection tube (2m)</td>
			<td>Eppendorf</td>
			<td>524616004</td>
			<td>This connects the needle holder to the syringe during transplantation</td>
		</tr>
		<tr>
			<td>Microinjection mold (plastic mold with wedge-shaped protrusions)</td>
			<td>Adaptive Science Tools</td>
			<td>PT-1</td>
			<td>alternatives with similar shape can be use</td>
		</tr>
		<tr>
			<td>microneedle holder</td>
			<td>Narishige</td>
			<td>M-152</td>
			<td>any alternative that fits the outside diameter of the injection needles can be used</td>
		</tr>
		<tr>
			<td>microinjector</td>
			<td>Narishige or Eppendorf Femtojet</td>
			<td></td>
			<td>Pneumatic injector using gas pressure</td>
		</tr>
		<tr>
			<td>micromanipulator</td>
			<td>Coherent Scientific</td>
			<td>M330IR</td>
			<td>similar alternatives can be used</td>
		</tr>
		<tr>
			<td>microloader tip</td>
			<td>Eppendorf</td>
			<td>5242956003</td>
			<td></td>
		</tr>
		<tr>
			<td>Mineral oil</td>
			<td>Sigma</td>
			<td>M5904-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>needle puller</td>
			<td>Sutter Instruments</td>
			<td>Model P-2000</td>
			<td>Settings used for this puller are: H 430, Fil 4, Vel 50, Del 225, Pul 75. Any needle puller can be used if it results in appropriate tip dimension</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>Interpath</td>
			<td>PM996</td>
			<td>any paraffin film</td>
		</tr>
		<tr>
			<td>Pasteur pipette plastic</td>
			<td>Samco Scientific</td>
			<td>202</td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette glass</td>
			<td>Hirschmann Laborgeraete</td>
			<td>9260101</td>
			<td></td>
		</tr>
		<tr>
			<td>Pronase</td>
			<td>Sigma</td>
			<td>P5942-25MG</td>
			<td>&#160;Protease Type XIV</td>
		</tr>
		<tr>
			<td>N-phenyl thiourea</td>
			<td>Sigma</td>
			<td>P7629-25G</td>
			<td>PTU is toxic and can be prepared as a stock solution to avoid frequent exposure to the powder, consult MSDS before purchase / use.</td>
		</tr>
		<tr>
			<td>Qiaquick gel extraction</td>
			<td>Qiagen</td>
			<td>28704</td>
			<td>any alternatives to purify DNA can be used</td>
		</tr>
		<tr>
			<td>Rneasy Mini kit</td>
			<td>Qiagen</td>
			<td>74104</td>
			<td>any alternatives to purify RNA can be used</td>
		</tr>
		<tr>
			<td>SP6 mMessage kit</td>
			<td>Qiagen</td>
			<td>AM1340</td>
			<td>any alternatives to transcribe DNA using SP6</td>
		</tr>
	</tbody>
</table>

in vivo imaging of transgenic gene expression in individual retinal progenitors in chimeric zebrafish embryos to study cell nonautonomous influences

The genetic and technical strengths have made the zebrafish vertebrate a key model organism in which the consequences of gene manipulations can be traced in vivo throughout the rapid developmental period. Multiple processes can be studied including cell proliferation, gene expression, cell migration and morphogenesis. Importantly, the generation of chimeras through transplantations can be easily performed, allowing mosaic labeling and tracking of individual cells under the influence of the host environment. For example, by combining functional gene manipulations of the host embryo (e.g., through morpholino microinjection) and live imaging, the effects of extrinsic, cell nonautonomous signals (provided by the genetically modified environment) on individual transplanted donor cells can be assessed. Here we demonstrate how this approach is used to compare the onset of fluorescent transgene expression as a proxy for the timing of cell fate determination in different genetic host environments.
In this article, we provide the protocol for microinjecting zebrafish embryos to mark donor cells and to cause gene knockdown in host embryos, a description of the transplantation technique used to generate chimeric embryos, and the protocol for preparing and running in vivo time-lapse confocal imaging of multiple embryos. In particular, performing multiposition imaging is crucial when comparing timing of events such as the onset of gene expression. This requires data collection from multiple control and experimental embryos processed simultaneously. Such an approach can easily be extended for studies of extrinsic influences in any organ or tissue of choice accessible to live imaging, provided that transplantations can be targeted easily according to established embryonic fate maps.

This work presents an experimental protocol to assess changes in gene expression timing when wild type retinal progenitors develop within a morphant host embryo. The experimental host embryos are Ptf1a morphants, which lack the intermediate born horizontal and amacrine interneurons of the retina 7,26. These have been compared to control host embryos, which were injected with a standard control morpholino.
<p class="jove_conten...

Watch this Scientific Journal Video about In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences at JoVE.c

In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences

Live tracking of individual WT retinal progenitors in distinct genetic backgrounds allows for the assessment of the contribution of cell non-autonomous signaling during neurogenesis. Here, a combination of gene knockdown, chimera generation via embryo transplantation and in vivo time-lapse confocal imaging was utilized for this purpose.

In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences

The genetic and technical strengths have made the zebrafish vertebrate a key model organism in which the consequences of gene manipulations can be traced ...

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Live Imaging of Mouse Secondary Palate Fusion

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to ...

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain ...

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

The pancreas is a complex organ composed of many different cell types that work together to regulate blood glucose homeostasis and digestion. These cell ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...