Analysis and evolution of the TAPS gene family. G.E. Kovalick. Science and Mathematics, University of Texas of the Permian Basin, Odessa, TX.

   TAPS genes appear to encode a novel class of serine protease inhibitors. Many of these proteins have roles as mediators of inflammation and other immune responses. TAPS genes are ubiquitous in eukaryotes and appear to comprise a multigene family. However, the structure and function of these genes remain poorly characterized, almost nothing is known about the regulation and targeting of TAPS gene products, and identification of orthologous genes in different species has remained problematic. Two TAPS genes, Agrand Agr2 have been cloned and characterized in Drosophila. These genes lie 1.5 kb apart on the X chromosome and probably originated through gene duplication. Both are expressed in the midgut, but each has a distinctive expression pattern during development. With the completion of the Drosophilagenome sequence, it has become possible to search the genome for other TAPS genes. Multiple BLAST similarity searches were used to identify an additional 19 potential TAPS genes. Based on degree of sequence similarity and on intron positioning, these 21 genes could be grouped into 3 distinct subfamilies. Most TAPS genes belong to the first subfamily and encode proteins that are secreted. Subfamilies two and three contain one or a few members that encode intracellular proteins. Members of these latter subfamilies encode proteins with more sequence similarity to TAPS proteins from other species than to TAPS proteins from subfamily one. Members of each subfamily have been cloned and their expression patterns are currently being characterized. Similar BLAST searches were performed against the completed yeast and C. elegansgenomes. 3 TAPS genes were identified within the yeast genome and 36 within the C. elegansgenome. Interestingly, C. elegansTAPS genes can also be organized into subfamilies with characteristics similar to those found in Drosophila. This suggests that each subfamily represents a functional grouping that has been conserved between species.