Use of revertant cell lines to identify targets of v-fos transformation-specific alterations in gene expression.
Two proteins expressed in Rat-1 cells which are targets for v-fos transformation-specific alterations in gene expression were identified as alpha 1(I) and alpha 2(I) procollagen. While procollagen (I) proteins were synthesized in Rat-1 fibroblasts, their synthesis was dramatically reduced in Rat-1 cells transformed with the FBJ-v-fos oncogene. Revertant cell lines, which were previously shown to express a functional fos oncoprotein, resumed the synthesis of procollagen (I) at levels comparable to those seen in Rat-1 cells. Further results indicated that these procollagen proteins were also synthesized in Rat-1 cell lines that constitutively express high levels of a transfected c-fos protooncogene. Together, these observations suggested that constitutive fos protein expression was not sufficient to inhibit synthesis of these proteins. We have further demonstrated that Rat-1 cells transformed by most other oncogenes express abundant levels of procollagen (I), indicating that inhibition of procollagen (I) synthesis is not a general characteristic of transformed Rat-1 cells but is specifically associated with FBJ-v-fos-induced transformation. Northern blot analysis and runoff transcription assay data indicated that the alpha 1(I) procollagen, but not alpha 2(I) procollagen, is differentially regulated at the transcriptional level in Rat-1 fibroblasts, v-fos transformants, and revertants.
Hoemann
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Division of Toxicology, Whitaker College, Massachusetts Institute of Technology, Cambridge 02139.
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D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006031:Glycosylation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016761:Oncogene Proteins v-fos; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D011347:Procollagen / Q000096:biosynthesis* / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D014158:Transcription, Genetic
D016761:Oncogene Proteins v-fos; D009856:Oncogene Proteins, Viral; D011347:Procollagen; D012333:RNA, Messenger