Highly conserved glucose-regulated protein in hamster and chicken cells: preliminary characterization of its cDNA clone.

Abstract

A temperature-sensitive mutant K12 derived from a Chinese hamster fibroblast overproduces 3 specific proteins of MW 94,000, 78,000 and 58,000 when incubated at the nonpermissive temperature (40.5.degree. C). These proteins were previously identified as glucose-regulated proteins similar to those observed in chicken embryo fibroblasts when the cells are starved of glucose. The 78,000 MW proteins isolated from the hamster K12 cell line and from chicken embryo fibroblasts have identical electrophoretic mobilities in 2-dimensional isoelectric focusing gels and nearly identical peptide maps. These proteins are different from heat-shock proteins previously described for animal cells. A library of c[complementary]DNA clones was constructed by using the RNA extracted from the hamster K12 cells incubated at 40.5.degree. C. Clones that hybridize preferentially with cDNA made from RNA at 40.5.degree. C were selected. By using the hybrid-selection technique, followed by in vitro translation, a cDNA clone containing a 2550-nucleotide insert coding for the hamster MW 78,000 protein was identified.