Human annexin 31 genetic mapping and origin

The cDNA encoding novel human annexin 31 was utilized for chromosomal mappi ng, structural comparison, and phylogenetic analysis to clarify its genetic relationship to other annexins. The ANX31 gene locus was mapped by fluores cence in situ hybridization to human chromosome 1q21, remote from ten other paralogous human annexins on different chromosomes but near the epidermal differentiation gene complex, the S100A gene cluster and a breast-cancer tr anslocation region. Protein homology testing and characterization of incomp letely processed expressed sequence tags identified annexin 2 as the closes t extant homologue. Maximum likelihood analysis confirmed its most recent c ommon ancestor with vertebrate annexin 2 and validated its classification, in order of discovery, as annexin 31. This subfamily was formed approx. 500 -600 million years ago, subsequent to the gene duplication that produced an nexin 1. It has diverged rapidly and extensively, especially in the well-co nserved and functionally critical type II calcium-binding sites. (C) 1999 E lsevier Science B.V. All rights reserved.