Using the Tg(nrd:egfp)/albino Zebrafish Line to Characterize In Vivo Expression of neurod

Center for Regenerative Therapies Dresden, Germany
PLoS ONE (Impact Factor: 3.23). 01/2012; 7(1):e29128. DOI: 10.1371/journal.pone.0029128
Source: PubMed


In this study, we used a newly-created transgenic zebrafish, Tg(nrd:egfp)/albino, to further characterize the expression of neurod in the developing and adult retina and to determine neurod expression during adult photoreceptor regeneration. We also provide observations regarding the expression of neurod in a variety of other tissues. In this line, EGFP is found in cells of the developing and adult retina, pineal gland, cerebellum, olfactory bulbs, midbrain, hindbrain, neural tube, lateral line, inner ear, pancreas, gut, and fin. Using immunohistochemistry and in situ hybridization, we compare the expression of the nrd:egfp transgene to that of endogenous neurod and to known retinal cell types. Consistent with previous data based on in situ hybridizations, we show that during retinal development, the nrd:egfp transgene is not expressed in proliferating retinal neuroepithelium, and is expressed in a subset of retinal neurons. In contrast to previous studies, nrd:egfp is gradually re-expressed in all rod photoreceptors. During photoreceptor regeneration in adult zebrafish, in situ hybridization reveals that neurod is not expressed in Müller glial-derived neuronal progenitors, but is expressed in photoreceptor progenitors as they migrate to the outer nuclear layer and differentiate into new rod photoreceptors. During photoreceptor regeneration, expression of the nrd:egfp matches that of neurod. We conclude that Tg(nrd:egfp)/albino is a good representation of endogenous neurod expression, is a useful tool to visualize neurod expression in a variety of tissues and will aid investigating the fundamental processes that govern photoreceptor regeneration in adults.

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    • "We described, for the first time, that neurod mRNA and protein are very strongly rhythmically expressed in the zebrafish retina. This observation might explain some of the discrepancies in neurod expression reported previously (Ochocinska and Hitchcock, 2007; Nelson et al., 2008; Thomas et al., 2012), since its expression is highly dependent on the time of the day at which samples are collected, and whether the circadian clock is entrained or not. The ‘adult-like’ pattern of neurod expression at 96 hpf previously described by Ochocinska and Hitchcock (2007) is identical to the expression pattern that we observed for 6 dpf larvae at ZT3, ZT15 and ZT21. "
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