Alternative splicing of Pax5 in immune tissues of rainbow trout (Oncorhynchus mykiss) (81.4)

Abstract Pax5 is a master regulator of B cell development and regulates gene expression of a host of genes involved in cell maturation and activation. Previous studies on alternative splicing of Pax5 have reported on different isoforms that differ in DNA binding (encoded by exons 2 and 3) and trans-activation (TA) potential (encoded by exons 7-10). Our lab explores alternative splicing of Pax5 as a viable way of regulating downstream gene targets and hence, progression of the B cell program in rainbow trout. cDNAs from four trout immune tissues (anterior and posterior kidney, spleen and blood) were screened by nested PCR to search for alternatively spliced Pax5 transcripts. Several splice forms, lacking exons 2, 8 or 9, were uncovered. Using quantitative real-time PCR, the change in expression of each isoform is currently being analyzed in immune tissues stimulated in culture with LPS. This study will set the framework to better understand how alternative splicing can potentially regulate expression of target genes during B cell differentiation. This research is supported by a grant from the NIH and a graduate research grant from the A&S GSA.