Insights Into the Evolution of the /Blimp1 Gene Family in Teleost Fish.

In mammals, Blimp1 (B lymphocyte-induced maturation protein 1) encoded by the gene and its homolog Hobit (homolog of Blimp1 in T cells) encoded by , represent key transcriptional factors that control the development and differentiation of both B and T cells. Despite their essential role in the regulation of acquired immunity, this gene family has been largely unexplored in teleosts to date. Until now, one gene has been identified in most teleost species, whereas a homolog has not yet been reported in any of these species. Focusing our analysis on rainbow trout (), an identification and characterization of -like genes has been undertaken, confirming that and evolved from a common ancestor gene, acquiring three gene copies after the teleost-specific whole genome duplication event (WGD) and six genes after the salmonid-specific WGD. Additional transcriptional studies to study how each of these genes are regulated in homeostasis, in response to a viral infection or in B cells in different differentiation stages, provide novel insights as to how this gene family evolved and how their encoded products might be implicated in the lymphocyte differentiation process in teleosts.