Recombinant HEK293 cell line expressing human PDE7B (phosphodiesterase 7B, accession number NM_018945). ; Human PDE7B has been stably expressed in a human embryonic kidney (HEK293) cell line. PDE7B expression was confirmed by Western blotting. The function of expressed PDE7B was validated by cAMP detection assay. The regulation of intracellular level of cAMP by PDE7B in PDE7B stably-expressed HEK293cells was characterized by a cell-based reporter assay using pCRE-luc reporter vector. pCRE-luc contains the luciferase gene that is under the control of cAMP response element (CRE). Elevation of intracellular cAMP activates cAMP response element binding protein (CREB) to bind CRE and induces the expression of luciferase. When cells transiently transfected with pCRE-luc reporter were activated by forskolin, the level of cAMP was upregulated in parental HEK293 cells inducing the expression of the luciferase reporter whereas hPDE7B-HEK293 cells showed reduction in the level of cAMP that resulted in lowered expression of luciferase.