Expression of the Intermediate-Filament-Associated Protein Synemin in Chicken Lens Cells
Synemin, a 230-kilodalton polypeptide component of avian muscle and erythrocyte intermediate filaments, is also found in association with the vimentin filaments of lens tissue. In chicken lens cells, synemin is bound to the core vimentin polymer with the same 180-nm periodicity that it exhibits in erythrocytes. Its solubility properties are characteristic of those of intermediate filaments in general and similar to those of synemin in muscle cells and erythrocytes. Synemin appears at an early stage of lens development and undergoes a dramatic accumulation as the epithelial cells elongate and differentiate into fiber cells. In contrast to synemin in cultured skeletal muscle, lens synemin is not confined to postmitotic, terminally differentiating cells but is present in proliferative cells as well. It is lost from the fibers near the center of the lens, as are many other cellular structures including intermediate filaments. These findings provide new information about the occurrence and expression of avian synemin and new insight regarding its presumptive role as a modulator of intermediate-filament function.
Additional Information© 1984 American Society for Microbiology. Received 23 April 1984. Accepted 3 July 1984. We thank John Ngai for his comments on the manuscript. This work was supported by grants from the National Institutes of Health, National Science Foundation, and Muscular Dystrophy Association of America. B.L.G. was supported by a postdoctoral fellowship from the Muscular Dystrophy Association of America. E.L. is a recipient of a Public Health Service Research Career Development Award from the National Institutes of Health.
Published - GRAmcb84.pdf