The involvement of neural retina pax6 in lens fiber differentiation.
Proper eye formation depends on specific interactions between neural and ectodermal tissues coupled with temporally distinct gene expression and a regulated sequence of signaling events. The homeobox gene Pax6 is vitally important to the entire process of eye development in both vertebrates and invertebrates. Pax6 expression for the retina anlage has been shown to be indispensable in the development of various retinal cells. Here, we report that Pax6 expression in neural tissue plays an important role in lens development. Expression of a dominant-negative version of Pax6 isoform that lacks 5a-exon sequence in developing optic vesicles (OV) of chick embryos led to arrest of lens development at the lens vesicle stage as well as optic cup deformation. To gain insights into the molecular events underlying deformed lens formation, we examined the expression of several transcription factors in the lens of Pax6-negative-OV eye. Importantly, L-Maf was downregulated while c-Maf was found normal in deformed lens. We detected a downregulation of fibroblast growth factor (FGF8) in the neural tissue. Our in vivo experiments suggest that Pax6 in neural retina regulates FGF8 expression, which may maintain L-Maf expression in the lens to be essential for later lens fiber differentiation.
Reza
Hasan M
HM
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
Yasuda
Kunio
K
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology; D004627:Embryonic Induction / Q000502:physiology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D007908:Lens, Crystalline / Q000002:abnormalities* / Q000166:cytology / Q000378:metabolism; D050977:Maf Transcription Factors; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D055748:SOXB1 Transcription Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D007381:Intermediate Filament Proteins; C111440:L-MAF protein, Gallus gallus; D050977:Maf Transcription Factors; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D055748:SOXB1 Transcription Factors; D015534:Trans-Activators; D014157:Transcription Factors; C084808:phakinin; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors