Characterization of the human CREB3L2 gene promoter.

CREB3L2 encodes a member of the CREB3 family of transcription factors. We characterized its promoter region, showing that it is asymmetrically bidirectional, also driving the expression of a variant of AKR1D1. It has a CRE binding site which is conserved among mammalians; removal or alteration of it resulted in reduced promoter activity. When transiently transfecting the HEK293 cell line with constructs with partially deleted promoter regions, 5' deletions beyond 1058-bp upstream of the transcription starting site resulted in successive reduction of the activity. The inclusion of the untranslated part of CREB3L2 exon 1 strongly inhibited the promoter activity. Forskolin resulted in a decreased reporter activity, whereas phorbol 12-myristate 13-acetate increased the promoter activity irrespective of the status of the CRE binding site. The presence of the CRE site indicates autoregulation of CREB3L2 and/or regulation via other members of the CREB3 family or a variety of bZIP transcription factors.