Regulation of the human platelet-derived growth factor B-chain gene.

Human platelet-derived growth factor (PDGF) B chain is a cellular homologue of v-sis, closely involved in cell growth and oncogenicity. Analysis in this study showed the importance of not only the region near the TATAA box but also the fragment -355 bases or more upstream in the expression of the PDGF-B chain gene. However, tissue specificity was not clear in the 5' upstream region alone, and regulation by gene methylation or by elements other than in the 5' region seemed to be necessary. In A172 cells, the half-life of mRNA was much shorter in the PDGF-B chain (< 2 hours) than in the PDGF-A chain (7 hours). Regulation of the PDGF-B chain gene may markedly differ from that of the PDGF-A chain gene not only at the transcriptional level but also at the post-transcriptional level.