Characterization of the mouse apolipoprotein Apoa-1/Apoc-3 gene locus: Genomic, mRNA, and protein sequences with comparisons to other species

In this report we present the genomic, cDNA, and predicted protein sequences for mouse apolipoproteins A-I and CIII, as well as sequence comparisons with other species. The genes for these apolipoproteins are within 2.5 kb of each other and convergently transcribed. The almost 9 kb of genomic sequence presented extends from 1298 bp 5′ to the apolipoprotein A-I ( Apoa-1 ) gene to 1249 bp 5′ to the apolipoprotein CIII ( Apoc-3 ) gene. The mouse Apoa-1 gene is 1.76 kb in length with four exons and three introns. The 5′ flanking region contains TATA and CCAAT box sequences, an interferon responsive element homology, and potential binding sites for transcription factors CTF/NF 1 and HNF 4 . Translation of the cDNA predicts that the mouse Apoa-1 primary transcript is 264 amino acids. The mouse Apoc-3 gene is 2.2 kb in length and also consists of four exons and three introns. The 5′ flanking region contains TATA and CCAAT box sequences, RXR-1 and ARP-1 binding sites, and potential binding sites for transcription factors HNF 4 , NFkB, AP-1, and CTF/NF 1 . Translation of the cDNA predicts that the mouse Apoc-3 primary transcript is 99 amino acids. The clustering and genomic organization of the mouse Apoa-1 and Apoc-3 genes are similar to those of the rat and human genes. Significant sequence homologies between species exist for the proximal promoter and exonic regions of each gene, but not for the intronic or intergenic regions. The mouse apo A-I protein is 66 to 68% homologous to human, rat, and rabbit apo A-I, whereas the mouse apo CIII protein is 63 to 81% homologous to human, rat, and dog apo CIII. The gene complex appears to be similar in all mammals studied, and the elucidation of its structure in the mouse will contribute to our ability to examine the regulation and physiologic role(s) of these genes in vivo .