ROGERS, S.A.*; CHANG, Y.; Arizona State University; Arizona State University: Evolution of Regulatory Elements that Control Tissues-Specific Expression of Recombination Activation Genes

Tracking the evolution of cis-regulatory sequences is a difficult task because of the lack of knowledge about the structure of these elements and their relationship to their function. Gaining a better understanding of the evolutionary mechanism could elucidate differences in gene expression seen between species. Using a genomic comparative approach, we have examined the evolutionary process of transcriptional regulation for recombination activation genes (RAG1 and RAG2) in zebrafish, tetraodon, fugu, frog, mouse, macaque, chimp and human. We found some regulatory elements upstream of 5� RAG2 that are only present in lower vertebrates, but not in higher vertebrates. It has been shown that RAG1 and RAG2 gene expression exhibit different tissues specificity profiles between teleosts and mammals, and our findings could have important implications for understanding the tissue-specific regulation of RAG1/2 expression among various organisms.