Oct2

Oct-2, also written Oct2, is a transcription factor belonging to the POU family. In humans it is encoded by the POU2F2 gene. The protein binds to the octamer motif, a DNA sequence found in numerous gene regulatory elements, and plays a role in directing gene expression programs in developing and mature B cells.

Oct-2 contains the characteristic POU domain, formed by a POU-specific subdomain and a homeodomain, which together enable sequence-specific DNA binding. It often functions in conjunction with B cell–specific cofactors, most notably OBF-1 (POU2AF1), to activate transcription from immunoglobulin gene promoters and enhancers. The interaction with these coactivators modulates Oct-2 activity and helps recruit the transcriptional machinery.

Expression of Oct-2 is highest in B lymphocytes and plasma cells, with more limited presence in other tissues. In B cells, Oct-2 helps regulate immunoglobulin gene expression and supports aspects of B cell differentiation and maturation, contributing to the proper development of the antibody repertoire. Its activity can influence decisions among alternative transcriptional programs during B cell ontogeny.

Clinical and research relevance of Oct-2 centers on its role as a regulator of humoral immunity. Studied mainly in the context of B cell biology, Oct-2–driven transcription intersects with immunoglobulin gene control and lineage-specific transcriptional networks governed by POU-family factors. The protein is conserved across vertebrates, reflecting its fundamental function in immune system regulation and transcriptional control mechanisms.

See also: POU family transcription factors; POU2F1; POU2AF1; OBFC1; immunoglobulin gene regulation.