MULTIPLE GENE DUPLICATION AND EXPRESSION OF MOUSE BCL-2-RELATED GENES, A1

Here we report the genomic cloning and characterization of the murine A1 genes, which belong to the bcl-2 gene family. Southern analysis ind icated the existence of at least four A1 genes in the murine genome an d four different A1 genes, designated A1-a, -b, -c and -d, were cloned from the murine genomic library. The Al-a, -b and -d genes consisted of two exons, whereas the A1-c gene contained 1 bp insertion in the co ding region which may result in an aberrant and truncated protein by f rame-shift. With the exception of A1-c, the coding regions among A1 ge nes are highly conserved at >97% at the nucleotide level and at >96% a t the amino acid level. A1-a, -b and -d genes appeared to be expressed specifically in organs containing many neutrophils, In neutrophils, A 1-a, -b and -d transcripts were detected at a comparable level. Our da ta suggest that the multiple Al genes in mice were generated by gene d uplication and each of them may function as anti-apoptotic molecules i n neutrophils.