| First Author | Hsueh YP | Year | 1995 |
| Journal | J Immunol | Volume | 154 |
| Issue | 11 | Pages | 5675-83 |
| PubMed ID | 7751619 | Mgi Jnum | J:25539 |
| Mgi Id | MGI:73255 | Doi | 10.4049/jimmunol.154.11.5675 |
| Citation | Hsueh YP, et al. (1995) Overexpression of activation transcriptional factor 1 in lymphomas and in activated lymphocytes. J Immunol 154(11):5675-83 |
| abstractText | cAMP-regulated gene expression always involves a conserved cAMP-responsive element (CRE) present in the promoter of cAMP-inducible genes. Two of the highly related proteins, cyclic AMP-responsive element binding protein (CREB) and activation transcriptional factor 1 (ATF-1), have been shown to activate transcription in response to cAMP by interacting with CRE. However, ATF-1 is a much weaker mediator of cAMP response, and its functional role in vivo remains unclear. Here we report a significant enhancement of ATF-1 expression in most transformed lymphocytes. Little variation in CREB level was observed, however. The activation of normal T lymphocytes induced a transient increase of ATF-1 expression to a level comparable to that of T lymphomas. Activation had no effect on the ATF-1 level of transformed T lymphocytes. The induction of ATF-1 required the costimulation of normal T lymphocytes with TPA and A23187. TPA, Ca2+ ionophore, or cAMP alone did not stimulate ATF-1 expression in normal lymphocytes. Nuclear run-on assay indicates that the increased ATF-1 expression in T cell lymphomas and in activated splenic T lymphocytes was not due to an enhanced transcription. Instead, an increase in ATF-1 mRNA stability was found in these lymphocytes. The regulation of ATF-1 expression through RNA stability in cells of different states suggests that ATF-1 may play an active role in cell growth and differentiation. |
