The expression of chick alpha A2-crystallin RNA during lens development and transdifferentiation

Abstract

During development of the vertebrate lens, the lens epithelium undergoes a final stage of differentiation into lens fibre cells, during which the major lens proteins, the crystallins, are synthesised. Lentoids, comprising clusters of lens fibre cells can also be produced by transdifferentiation from certain non-lens tissues, including neural retina and pigmented retinal epithelium. We have isolated an .alpha.A2-crystallin genomic probe and used it to study the transcription and processing of .alpha.A2-crystallin mRNA both during lens development and transdifferentiation. We relate these results to earlier measurements in this laboratory of .delta.-crystallin transcription and .alpha.- and .delta.-crystallin protein synthesis, to compare the expression of these two sets of genes. Tissue specific differences in gene expression were found. .delta.-Crystallin mRNA is transcribed before .alpha.A2-crystallin RNA in the lens, but after it in transdifferentiating neural retina and pigmented epithelia.