Quantitation of PAX6 and PAX6(5a) transcript levels in adulthuman lens, cornea, and monkey retina

[摘要] Purpose: PAX6 is a critical regulator of the developing lens, otherocular tissues, central nervous system, and pancreas. There are twoalternatively spliced forms of the protein, PAX6 and PAX6(5a), that mayhave different regulatory functions. This study was designed todetermine the amounts of PAX6 and PAX6(5a) transcripts present in adulthuman lens epithelium and fibers, human cornea and monkey retina.Methods: PAX6 and PAX6(5a) transcript levels were monitored inmicrodissected lens epithelia, lens fibers, whole lens, cornea, andretina by competitive RT-PCR. The levels of TBP/TFIID were examined inadult human lens epithelium and fibers as control.Results: PAX6 and PAX6(5a) were expressed at equal levels in lensepithelium and fibers. Ninety-five times more PAX6 transcripts weredetected in the epithelial cells than in the fibers. Adult human corneaand monkey retina expressed less PAX6/PAX6(5a) than lens epithelium butmore than lens fibers. Correspondingly, 40 fold higher levels of TBPtranscripts were detected in lens epithelium than fibers, suggestingreduced overall expression of transcription factors in the adult lensfibers.Conclusions: The presence of PAX6 and PAX6(5a) messages and proteinsin adult lens epithelium suggest functions for both forms of PAX6 in thegrowth and maintenance of the adult human lens. The reduced levels ofboth forms of PAX6 in the lens fibers suggest down regulation of thisgene during differentiation of epithelia into fibers. The lower level ofTBP expression in lens fibers also suggests reduced transcriptionalcompetence of adult lens fibers.

[学科分类] 生物化学/生物物理