Purpose: The lens of the eye assembles two distinct intermediate filament protein-based networks. One network is composed of vimentin, and has been immunocytochemically demonstrated in the epithelial cells and younger fiber cells. The second network is composed of CP49/CP115, two lens-specific IF-like proteins, and is seen in the younger fiber cells and more mature fiber cells, but not the lens epithelium. Proteolysis is known to play a role in the differential distribution of these proteins, but the role of tranccriptional regulation has not been explored. Methods In situ hybridization was used to localize transcripts of vimentin, CP49 and CP115 in lenses of embryonic chicks. Results Vimentin transcripts were detectable in the lens epithelial cells, while CP49 and CP115 transcripts were detectable only in the differentiating fiber cell. Conclusions The presence CP49/CP115 in, and the loss of vimentin from the newly differentiated fiber cell is not due solely to differential proteolysis, but requires differentiation-specific transcriptional regulation as well. Thus, mRNA distribution is consistent with a genetically programmed developmental switch from a vimentin-based intermediate filament network, to a CP49/CP115 based Beaded Filament network during terminal differentiation. The biological advantage conferred by such a switch has not been determined.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 1997|
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