In this paper, the human phosphodiesterase 7A1 (hPDE7A1) promoter region was identified and functionally characterized. Transient transfection experiments indicated that a 2.9 kb fragment of the hPDE7A1 5′-flanking region, to position −2907, has strong promoter activity in Jurkat T-cells. Deletion analysis showed that the proximal region, up to position −988, contains major cis-regulatory elements of the hPDE7A1 promoter. This minimal promoter region contains a regulatory CpG island which is essential for promoter activity. The CpG island contains three potential cAMP-response-element-binding protein (CREB)-binding sites that, as judged by in vivo dimethyl sulphate (DMS) footprinting, are occupied in Jurkat T-cells. Moreover, over-expression of CREB results in increased promoter activity, but, on the other hand, promoter activity decreases when a dominant-negative form of CREB (KCREB) is over-expressed. In vivo DMS footprinting strongly indicates that other transcription factors, such Ets-2, nuclear factor of activated T-cells 1 (NFAT-1) and nuclear factor κB (NF-κB), might also contribute to the regulation of hPDE7A1 promoter. Finally, hPDE7A1 promoter was found to be induced by treatment with PMA, but not by treatment with dibutyryl cAMP or forskolin. These results provide insights into the factors and mechanisms that regulate expression of the hPDE7A gene.
- cAMP-response-element-binding protein (CREB)
- CpG island
- phorbol ester
Abbreviations used: CRE, cAMP-response element; CREB, cAMP-response-element-binding protein; NFAT-1, nuclear factor of activated T-cells 1; NF-κB, nuclear factor κB; DMS, dimethyl sulphate; PDE, phosphodiesterase; h, human; RACE, rapid amplification of cDNA ends; db-cAMP, dibutyryl cAMP; PKA, protein kinase A; PKC, protein kinase C.
- The Biochemical Society, London ©2003