Oncogenic transformation-dependent expression of a transcription factor NF-Y subunit.
As a result of differential splicing, one subunit of the nuclear factor Y (NF-Y) consists of two major isoforms designated short (NF-YaS) and long (NF-YaL). In proliferating normal human fibroblasts, NF-YaL is by far the more expressed isoform. Surprisingly, NF-YaS was found by immunoblotting to be as prominent as NF-YaL in simian virus 40 (SV40)-transformed cell derivatives. As a consequence, two NF-Y/DNA complexes, one containing the long and the other the short isoform, were formed with extracts from transformed cells and a target promoter element in electrophoretic mobility-shift assays. Only the complex containing NF-YaL was detected with extracts from normal fibroblasts. Furthermore, the NF-Y recognition motif contributed to promoter activation in SV40-transformed cells but not in normal, cells. Our finding links transcription stimulation in transformed cells to quantitative changes in the expression of an NF-Ya subunit.
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D002472:Cell Transformation, Viral / Q000235:genetics*; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D015689:Oncogene Protein p21(ras) / Q000502:physiology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D012326:RNA Splicing; D051381:Rats; D011916:Rats, Inbred F344; D013539:Simian virus 40; D013696:Temperature