Characterization of a far upstream located promoter expressing the acetyl-CoA carboxylase-alpha in the brain of cattle

Abstract

The expression of the bovine acetyl-CoA carboxylase-alpha-encoding gene (ACACA) was known to be controlled by three promoters. Here, we characterized a fourth promoter (PI) located 41kb upstream of the adjacent nutritionally-regulated promoter PIA on bovine chromosome 19. Our results showed that PI is an intergenic promoter driving expression of ACACA and conceivably, by analogy with the homologous genomic arrangement in sheep a component of the chromatin-modifying complex gene (TADA2L). 5′-RACE experiments defined the 3′ boundary of the promoter and a novel exon 1 comprising 263bp. It features at position +226 an ORF encoding an N-terminally extended ACC-α enzyme. The PI sequence is GC-rich, has no TATA box and CAAT box, similar to the homologous promoters in sheep, mouse and human. Expression profiles showed that PI is the promoter driving expression of the dominant ACACA-transcript in brain. Reporter gene assays in HC-11 cells indicated that deletion of extended promoter segments harboring putative cAMP response elements (CRE) clustered in the distal promoter region and specificity protein 1 (Sp1) attachment sites lowered PI activity.