Requirement of the carboxy‐terminal domain of RNA polymerase II for the transcriptional activation of chromosomal <i>c‐fos</i> and <i>hsp</i>70A genes

Abstract

The carboxy-terminal domain of the large subunit of mouse and human RNA polymerase II contains 52 repeats of a heptapeptide which are the targets for a variety of kinases. We have used an alpha-amanitin resistant form of the large subunit of pol II to study the role of the carboxy-terminal domain in the expression of chromosomal genes. The large subunit of RNA polymerase II and deletion mutants thereof, which contain only 31 (LSdelta31) and 5 (LSdeltaS) repeats, were expressed in 293 cells. Subsequently, the endogenous large subunit of RNA polymerase II was inhibited by alpha-amanitin and the induction of chromosomal c-fos and hsp70A genes was determined. Cells expressing the large subunit of RNA polymerase II and LSdelta31 were able to transcribe the c-fos and hsp70A genes after treatment with the phorbolester TPA and after heat-shock, respectively. In contrast, cells expressing LSdelta5 failed to induce expression of both genes.