title: Uncoupled expression of mRNAs for alpha 1(I) and alpha 2(I) procollagen chains in chemically transformed Syrian hamster fibroblasts.
abstract: Syrian hamster embryo fibroblasts transformed by 4-nitroquinoline-1-oxide (NQT-SHE cells) failed to synthesize the pro-alpha 1(I) subunit of type I procollagen but continued to synthesize altered forms of the other subunit, pro-alpha 2(I) (Peterkofsky, B., and Prather, W. (1986) J. Biol. Chem. 261, 16818-16826). This was unusual, since synthesis of the two subunits generally is coordinately regulated. Present experiments using cell-free translation and hybridization of RNA from normal and transformed Syrian hamster fibroblasts with labeled pro-alpha 1(I) DNA probes show that mRNA for pro-alpha 1(I) is absent from the transformant. In contrast, dot-blot and Southern blot hybridizations of cellular DNAs with pro-alpha 1(I) DNA probes demonstrated that the transformed cells contained pro-alpha 1(I) gene sequences and that the gross structure of the gene was unchanged by transformation. mRNA for the other type I procollagen subunit, pro-alpha 2(I), was present in transformed cells and the major collagenous polypeptide translated from this RNA migrated like the normal pro-alpha 2 subunit during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The translated procollagen chain was cleaved to an alpha 2(I)-sized collagen chain by pepsin at 4 degrees C. These studies provide a molecular basis for the observed collagen phenotype of NQT-SHE cells.
mesh_terms: D015112:4-Nitroquinoline-1-oxide; D000818:Animals; D002461:Cell Line, Transformed; D002474:Cell-Free System; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D009693:Nucleic Acid Hybridization; D011347:Procollagen / Q000096:biosynthesis / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits
chemical_list: D011347:Procollagen; D012333:RNA, Messenger; D015112:4-Nitroquinoline-1-oxide; D004247:DNA