CD79B Gene

The CD79B gene (CD79b molecule/Ig-beta) is a protein-coding gene located on chromosome 17q23. Alternatively spliced transcript variants encoding different isoforms have been described.

The CD79B gene encodes the Ig-beta protein of the B-cell receptor complex. The B lymphocyte antigen receptor is a multimeric complex containing the antigen-specific component, surface immunoglobulin (Ig). The surface immunoglobulin associates non-covalently with two other proteins, Ig-alpha and Ig-beta, which are necessary for the expression and function of the B-cell antigen receptor. Ig-alpha and Ig-beta are encoded by different genes(CD79A gene/CD79B gene).

CD79B mutations are also detected in approximately 30% of patients with CD5+ DLBCL lymphoma . CD79B mutations are preferentially associated with localized DLBCL (Takeuchi T et al.2017).

The protein encoded by the CD79B gene (Ig-beta protein), in cooperation with the protein Ig-alpha encoded by the CD79A gene , is required for initiation of the signal transduction cascade activated by the B-cell antigen receptor complex (BCR), leading to internalization of the complex, trafficking to endosomes, and antigen presentation. Ig-beta enhances phosphorylation of Ig-alpha, possibly by recruiting kinases that phosphorylate this protein or by recruiting proteins that bind to Ig-alpha and protect it from dephosphorylation.

Diseases associated with CD79B include:

Agammaglobulinemia 6, mutation in CD79B.

1. Dobbs AK et al (2007) Cutting edge: a hypomorphic mutation in Ig-beta (CD79b) in a patient with immunodeficiency and a leaky defect in B cell development. J Immun 179: 2055-2059.
2. Ferrari S et al (2007) Mutations of the Ig-beta gene cause agammaglobulinemia in man. J Exp Med 204: 2047-2051.
3. Takeuchi T et al.(2017) MYD88, CD79B, and CARD11 gene mutations in CD5-positive diffuse large B-cell lymphoma. Cancer 123:1166-1173.