Nuclear matrix proteins of bovine corneal and conjunctival epithelium.

Purpose: To present a preliminary biochemical and immunochemical analysis of nuclear matrix proteins isolated from ocular surface epithelium.

Methods: Nuclear matrix protein-enriched fractions were prepared from bovine corneal and conjunctival epithelial cells. The preparations were analyzed by 1D and 2D SDS-PAGE and Western immunoblotting.

Results: A comparison of corneal and conjunctival nuclear matrix preparations using 1D and 2D SDS-PAGE revealed subsets of both common and apparently unique proteins. Western immunoblotting analysis to corneal nuclear matrix preparations with antibody to nuclear lamins confirmed the presence of these proteins in the preparation. 1D and 2D immunoblotting analysis of corneal nuclear matrix preparations with antibodies to the keratin K12 revealed the presence of two protein species.

Conclusions: Preliminary biochemical analysis of ocular surface nuclear matrix provides evidence for cell-type specific components of this structure. Immunochemical analysis of corneal epithelial nuclear matrix preparations suggests that two keratin K12 pools may exist in these cells, one pool associated with the cytoplasmic intermediate filament network, and a second pool closely associated with the nuclear matrix framework. Keratin K12 may therefore play a role in the regulation of corneal epithelial cell gene and protein expression via its association with the nuclear matrix.