cDNA cloning of a novel bHLH-PAS transcription factor superfamily gene, BMAL2: its mRNA expression, subcellular distribution, and chromosomal localization.

We isolated a human cDNA encoding a novel member of the bHLH-PAS transcription factor superfamily, BMAL2, which is highly similar to, but distinct from, BMAL1. The composite cDNA covered a 1720-bp sequence consisting of a putative 1653-bp open reading frame encoding a polypeptide of 551 amino acids. The deduced BMAL2 product contains a bHLH-PAS domain in its N-terminal region and a variable C-terminus. The overall identity of BMAL2 polypeptide to that of human BMAL1 is 49%. RNA analysis revealed that expression of BMAL2 transcripts was restricted to the fetal brain and to the adult liver in human, while human BMAL1 mRNA was expressed in the brain and skeletal muscle. The chromosomal localization of the human BMAL2 gene was determined by fluorescent in situ hybridization to be localized on chromosome 12 at region p12.2-p11.2. These results suggest that BMAL2 may play different roles from BMAL1 in the embryonic brain and in adult mammals.