STRUCTURE OF THE GENE ENCODING ANCHORIN-CII (CHICK ANNEXIN V)

Anchorin CII (annexin V) was first characterized as a collagen-binding protein and later identified as the chick homologue of human endonexi n II, a member of the annexin gene family. Its gene (anx5) structure a nd sequence have been investigated to provide insight into the evoluti on and regulation of this important protein, and to elucidate its puta tive role in signal transduction and cellular differentiation. Four ch ick genomic clones encoding anchorin CII were isolated and characteriz ed by restriction analysis, Southern blotting and sequencing. The anch orin CII-encoding gene spans about 24 kb and consists of 13 exons rang ing in length from 50 to 561 bp, interrupted by 12 introns of 94 bp to 7 kb. Its promoter sequence contained no TATA box, but did display a high GS C content and multiple Spl-binding sites typical of 'housekeep ing' genes. Potential binding sites for transcription factors in the 5 '-upstream region are consistent with regulation of anx5 expression by mitogens, oncoproteins, steroids and possibly metals. Genomic Souther n blotting confirmed that chick anx5 is present as a single-copy gene.