This investigation characterizes a prominent nuclear matrix protein isolated from tissue cultured mouse lens epithelial cells. The nuclear matrix protein was isolated using a modified Penman technique. Total nuclear matrix proteins were further separated by SDS-polyacrylamide gel electrophoresis. The SDS-PAGE profile of the nuclear matrix proteins displayed a prominent doublet band at 60 kDa region. Nonequilibrium 2D gel electrophoresis revealed that this protein is a basic nuclear protein. This 60 kDa protein was further characterized by comparing its internal peptide amino acid sequence with known protein sequence using the BLAST technique, and this study demonstrated that 60 kDa nuclear matrix protein displays significant sequence similarity with Xenopus Laevis heat shock transcription factor. We also raised antibodies against 60 kDa nuclear matrix protein. Immunofluorescence, studies showed that this 60 kDa nuclear matrix protein preferably decorates nucleus, and puncted pattern of fluorescence suggest presence of this protein in the discrete areas of the nucleus. Heat shock transcription factors upregulate synthesis of heat shock proteins and many of these protein act as molecular chaperones. Thus, presence of a nuclear matrix protein with significant sequence similarity with heat shock transcription factor suggests sustained heat shock protein synthesis in the mouse lens cells.
Copyright 2001 Wiley-Liss, Inc.