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In Ovo Electroporation in Embryonic Chick Retina
Published on: February 5, 2012
Quantitative estimation of RNA transcripts suggests persistence of Pax-6 expression in the postembryonic chick retina
S P Bhat1, S A Rayner, C M Huang
1Jules Stein Eye Institute, University of California School of Medicine, Los Angeles, Calif. 90095-7000, USA. bhat@jsei.ucla.edu
Insights
Pax-6 transcripts are present in the mature chick retina, decreasing by day 17 but increasing by day 31 and adulthood. This suggests retinal cells may retain proliferative potential longer than previously thought.
Area of Science:
- Developmental Biology
- Neuroscience
- Ophthalmology
Background:
- Paired box gene 6 (Pax-6) is crucial for early embryonic eye development.
- Its expression patterns in the functionally mature retina are not well understood.
- Pax-6 is associated with cell proliferation and differentiation.
Purpose of the Study:
- To investigate the expression of Pax-6 transcripts in the developing and mature chick retina.
- To determine if Pax-6 expression changes over time in retinal cell layers.
- To explore the implications of Pax-6 expression for retinal cell proliferation.
Main Methods:
- In situ hybridization was used to detect Pax-6 transcripts in chick retinas at various posthatching days (3, 10, 17, 31) and in adult chicks (2-3 months).
- Quantitative analysis, including competitive RT-PCR, was employed to measure Pax-6 transcript levels.
- Analysis was performed relative to both total tissue weight and total RNA content.
Main Results:
- Pax-6 transcripts were detected in the ganglion cell and amacrine cell layers of retinas from day 3 to adult.
- A significant reduction in Pax-6 transcripts was observed by day 17 compared to day 3.
- Transcript levels increased by day 31 and in adult retinas compared to day 17, suggesting sustained expression.
Conclusions:
- Pax-6 expression persists in specific retinal cell layers of the mature chick.
- The observed changes in Pax-6 transcript levels suggest dynamic regulation throughout retinal development and maturation.
- These findings imply that retinal cells in the ganglion and inner nuclear layers may retain proliferative potential into young adulthood.
Abstract:
Pax-6 is expressed during early embryonic development of the eye. Very little is known about its expression in the functionally mature retina. We have detected Pax-6 transcripts in the ganglion cell- and amacrine cell layers at days 3, 10, 17 and 31 posthatching and in 2- to 3-month-old chick retina by in situ hybridization. These observations were confirmed by a quantitative analysis. Competitive RT-PCR with a homologous internal control revealed a significant reduction (p < 0.001) in the number of Pax-6 transcripts in day 17 retina [(0.39 +/- 0.13) x 10(10)/mg tissue] compared to day 3 retina [(1.65 +/- 0.48) x 10(10)/mg tissue]. Although significantly lower than at day 3, the day 31 retina [(0.7 +/- 0.16) x 10(10)/mg tissue] and retina from 2- to 3-month-old chicks [(0.9 +/- 0.28) x 10(10)/mg tissue] contained an increased number of Pax-6 transcripts in comparison to day 17. On the basis of the amount of RNA, the number of Pax-6 transcripts in the day 3 retina [(0.45 +/- 0.14) x 10(10)/microg RNA] relative to day 17 retina [(0.4 +/- 0.08) x 10(10)/microg RNA] did not change significantly (p = 0.29). However, at day 31 and at 2-3 months of age an increased number of Pax-6 transcripts [(0.65 +/- 0.14) x 10(10)/microg RNA and (0.65 +/- 0.2) x 10(10)/microg RNA, respectively)] were found. In view of the known association of Pax-6 expression with proliferation and emergence of different cell types, these data suggest that cell types in ganglion and inner nuclear cell layers may retain proliferative potential for an extended period in the young adult retina.
