Cloning and functional activity of a novel truncated form of annexin IV inmouse macrophages

Annexin TV was cloned and sequenced from a mouse bone marrow-derived macrop hage cDNA library, and was found to exist as three different alternatively spliced transcripts. One transcript contained an additional 688 base pairs inserted within the coding region of the gene including an in-frame stop co don, Translation of this transcript in vitro confirmed the premature arrest of translation which resulted in a truncated annexin IV protein of approxi mately 22 kDa, Libe other members of the annexin family, the product of the wild-type annexin IV transcript bound in a calcium-dependent manner to bot h phenyl-sepharose and phospholipid vesicles. In contrast, the truncated an nexin IV product bound to these substrates in a Ca2+-independent fashion. T he existence of a novel form of annexin IV in mouse macrophages may aid in further defining the role of members of the annexin family. (C) Academic Pr ess.