| First Author | Baskaran R | Year | 1997 |
| Journal | J Biol Chem | Volume | 272 |
| Issue | 30 | Pages | 18905-9 |
| PubMed ID | 9228069 | Mgi Jnum | J:41960 |
| Mgi Id | MGI:894872 | Doi | 10.1074/jbc.272.30.18905 |
| Citation | Baskaran R, et al. (1997) Tyrosine phosphorylation of RNA polymerase II carboxyl-terminal domain by the Abl-related gene product. J Biol Chem 272(30):18905-9 |
| abstractText | The largest subunit of RNA polymerase II contains a C-terminal repeated domain (CTD) that is the site of phosphorylation by serine (threonine) and tyrosine kinases. Phosphorylation of the CTD is correlated with transcription elongation. A number of different kinases have previously been shown to phosphorylate the CTD; among them is a nuclear tyrosine kinase encoded by the c-abl proto-oncogene. The processive and high stoichiometric phosphorylation of RNA polymerase II by c-Abl requires the tyrosine kinase, the SH2 domain, and a CTD-interacting domain (CTD-ID) in the Abl protein. The physiological tyrosine phosphorylation of RNA polymerase II by c-Abl in DNA damage response has previously been demonstrated. Basal tyrosine phosphorylation of RNA polymerase II, however, is observed in cells derived from abl-deficient mice, indicating the existence of other CTD tyrosine kinases. In this report, we show that the tyrosine kinase encoded by an Abl-related gene (Arg) also phosphorylates the CTD in vitro and in transfected cells. The SH2 and kinase domain of Arg are 95% identical to that of c-Abl. However, these two proteins share only 29% identity in the large C-terminal region. Interestingly, a CTD-ID is also found in the C-terminal region of Arg. Mapping studies and sequence analysis have led to the identification of the CTD-ID that is highly conserved among the divergent C-terminal regions of Abl and Arg. These results indicate that tyrosine phosphorylation of RNA polymerase II CTD could be catalyzed by either c-Abl or Arg kinase. |
