Functional characterization of the human phosphodiesterase 7A1 promoter

Abstract

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, overexpression of CREB results in increased promoter activity, but, on the other hand, promoter activity decreases when a dominantnegative 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.

Overview of PDEs and Their Regulation

“…115 In Jurkat T cells, overexpression of CRE binding protein (CREB) increases the promoter activity. In human CD4…”

Discovery of BRL 50481 [3-(N,N-dimethylsulfonamido)-4-methyl-nitrobenzene], a Selective Inhibitor of Phosphodiesterase 7: In Vitro Studies in Human Monocytes, Lung Macrophages, and CD8+T-Lymphocytes

“…On the other hand, PDE7A2, which is generated by 5Ј-splicing and differs from PDE7A1 at its N terminus (Bloom and Beavo, 1996;Han et al, 1997), was never detected at the protein level, despite unequivocal identification of its mRNA (Smith et al, 2003). The distribution of PDE7A3 is largely unknown, but it has been found in human T-lymphocytes (Glavas et al, 2001) and may also be present in many PDE7A1-expressing cells as both transcripts are probably regulated by the same promoter (Torras-Llort and Azorin, 2003). In contrast, PDE7B is abundant in the brain, liver, heart, thyroid glands, and skeletal muscles, but it is not found in leukocytes (Gardner et al, 2000).…”

Phosphodiesterase-4: Selective and Dual-Specificity Inhibitors for the Therapy of Chronic Obstructive Pulmonary Disease

“…Studies by Glavas and coworkers (45) identified this splice variant in human CD4 ϩ T lymphocytes after costimulation with anti-CD3/CD28 antibodies, but its distribution in other cells is unknown. Given that PDE7A3 and PDE7A1 are probably regulated by the same promoter (43), it is possible that the expression pattern of the two transcripts is similar.…”

“…Two genes (PDE7A and PDE7B) have been identified in the mouse, rat, and human that encode PDE7 isoenzymes (36,(39)(40)(41)(42). The coding region of HSPDE7A spans 124 kb and contains 14 exons (43). Screening of murine and human skeletal muscle DNA libraries has identified three splice variants (PDE7A1, PDE7A2, and PDE7A3) derived from the same gene.…”