Pax-6 expression in posthatch chick retina during and recovery from form-deprivation myopia.
The expression of Pax-6 in fully-differentiated chick retina remains largely confined to the amacrine and ganglion cell layers. In the developing posthatch chick retina, Pax-6 expression shows a biphasic pattern; a decrease by posthatch day 17 followed by a steady increase in the adult eye. Interestingly, we find that this biphasic expression of Pax-6 is reflected in the biphasic growth pattern of the posthatch chick eye, which is disrupted by form-deprivation myopia (FDM). We have now examined the pattern of Pax-6 accumulation in 3-day-old chick eyes subjected to 2 weeks of FDM followed by 2 weeks of recovery from FDM. Quantitative RT-PCR (with a homologous internal control) revealed that after 2 weeks of occlusion the contralateral non occluded eyes, the occluded eyes and the normal nonexperimental chick eyes did not show any drastic changes in the number of Pax-6 transcripts. The data obtained suggests that the contralateral eye does not represent a 'normal' control eye; similar but nonidentical changes are seen, at the molecular level, in both the contralateral and the occluded eyes. Comparisons with the control nonexperimental animals, however, are meaningful. Even after 2 weeks of recovery under normal light conditions, the occluded eyes do not seem to reach the same level of Pax-6 expression (number of molecules per mg tissue) as seen in normal control eyes, suggesting that exposure of the posthatch chick eye to FDM impedes developmental progression that normally culminates in emmetropia.
Bhat
Suraj P
SP
Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA. bhat@jsei.ucla.edu
Rayner
Sylvia A
SA
Chau
Scott C
SC
Ariyasu
Reginald G
RG
D000818:Animals; D002645:Chickens; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics*; D007839:Functional Laterality / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D009216:Myopia / Q000503:physiopathology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D012160:Retina / Q000254:growth & development* / Q000378:metabolism / Q000503:physiopathology; D012683:Sensory Deprivation / Q000502:physiology*
D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D012097:Repressor Proteins