The murine lymphotoxin gene promoter. Characterization and negative regulation
| Autor: | S J Fashena, W L Tang, T Sarr, N H Ruddle |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 145:177-183 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.145.1.177 |
| Popis: | Murine lymphotoxin (LT; TNF-beta) gene upstream regulatory elements were identified by linking fragments of 5' DNA to the chloramphenicol acetyl transferase gene. Fragment LT1 (-293 to +77 in relation to the proximal cap site) exhibited promoter activity which drove CAT expression in transfected murine fibroblasts and T lymphomas. Primer extension analysis of endogenous LT message confirmed that LT1 contained the necessary elements required for promoter function. Promoter activity was not observed when LT2 (-662 to +77), LT3 (-1186 to +77), or LT3 delta AX (-1186 to +77 (delta-662/-269)) were ligated to the chloramphenicol acetyl transferase gene and transfected into fibroblasts or T lymphomas. At least one upstream repressor element is postulated to account for this promoter inhibition. In contrast to the results obtained with fibroblast and T cell transfectants, LT1 was inactive in the B cell transfectants A20 and P3X63. This suggests that some B cells express a repressor factor that inhibits the LT promoter and/or they lack the necessary positive regulatory factors. |
| Databáze: | OpenAIRE |
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