Molecular characterization and chromosomal mapping of porcine brain and muscle Arnt-like protein-1 gene

As a transcription factor regulating circadian rhythm, brain and muscle Arnt-like protein-1 (BMAL1) plays an important role in lipid homeostasis. The Chinese indigenous and western pig breeds show marked difference in fat deposition, the structure and function of porcine BMAL1 (pBMAL1) between them might be different. In present study, the molecular characteristics and chromosomal location of pBMAL1 were analyzed. The results indicated that pBMAL1 cDNA had a coding region of 1,878 bp and shared 94.36, 89.85 and 89.79% identity with human, mouse and rat BMAL1, respectively, and the pBMAL1 protein had 99.20, 98.24 and 97.92% identity to those of human BMAL1b, mouse BMAL1b and rat BMAL1b, respectively. Compared with other mammals, pBMAL1 was more closely related to human BMAL1. The expression of pBMAL1 was detected in kidney, stomach, spleen, bladder, gallbladder, lumbar spinal cord, medulla oblongata, heart, longissimus dorsi muscle, liver, small intestine, large intestine, lung and backfat tissues. In adipose tissues, it was detected in mesentery fat, leaf fat, caul fat, backfat and cardiac fat, however, the expression level was not significantly different. Alternative usage of exon 2 was revealed to result in two pBMAL1 transcripts. Finally, by using a whole genome porcine radiation hybrid (RH) panel (IMpRH), the pBMAL1 gene was mapped to SSC 2p11-q21.