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Gene Review

Cd79a  -  CD79A antigen (immunoglobulin-associated...

Mus musculus

Synonyms: B-cell antigen receptor complex-associated protein alpha chain, Ig alpha, Ig-alpha, Iga, Igalpha, ...
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Disease relevance of Cd79a


Psychiatry related information on Cd79a

  • Resulting Thyl-2+, L3T4+ cell lines depend on the T15 Id+ BCg3R-1d cells for growth and demonstrate the ability to bind TEPC15, a S107 germline-encoded, PC-specific Ig alpha [5].

High impact information on Cd79a

  • Early B-cell factor (EBF) is a cell type-specific transcription factor that is expressed at all antigen-independent stages of B-lymphocyte differentiation and participates in the regulation of the mb-1 gene [6].
  • Crosslinking Fc gamma RIIB with the surface immunoglobulin complex confers a dominant signal that prevents or aborts lymphocyte activation triggered through the ARH-1 motifs of the signal transduction subunits Ig-alpha and Ig-beta [7].
  • This inhibition is directly coupled to signalling mediated through Ig-alpha and Ig-beta as evidenced by chimaeric IgM/alpha and IgM/beta molecules [7].
  • A transfection experiment indicates that IgM-alpha is the product of mb-1, a B-cell specific gene encoding a transmembrane protein with sequence homology to proteins of the T-cell antigen receptor-CD3 complex [8].
  • Hence, Ig-alpha/beta are used in a sequential fashion for transduction of antigen and cognate T cell help signals [9].

Chemical compound and disease context of Cd79a

  • To determine whether a signal-competent Ig complex can already be assembled in the ER, we analyzed the consequence of pervanadate on tyrosine phosphorylation of Ig alpha in J558L plasmacytoma and 38B9 pre-B cells transfected with either a transport-competent IgL chain-pairing or an ER-retained nonpairing micro HC [10].

Biological context of Cd79a

  • In contrast, the expression of the mb-1 and LEF-1 genes was already reconstituted by the paired domain polypeptide lacking any transactivation function, suggesting that the DNA-binding domain of BSAP is sufficient to recruit other transcription factors to the regulatory regions of these two genes [11].
  • Here, we used in vivo footprinting assays to detect occupation of binding sites in endogenous mb-1 promoters at various stages of B-cell differentiation [12].
  • In transfection assays, selective methylation of a single CpG within the Pax-5-dependent Ets site greatly reduces mb-1 promoter activity [13].
  • Although B-lineage cells have only unmethylated mb-1 genes and do not modulate methylation of the mb-1 promoter during development, other tissues feature high percentages of methylated alleles [13].
  • These results point to the importance of the mIgM transmembrane region in mediating binding to accessory molecules, and provide support for a role of Ig-alpha and Ig-beta/gamma that extends beyond surface expression to signal transduction in B lymphocytes [14].

Anatomical context of Cd79a


Associations of Cd79a with chemical compounds

  • Ig beta Delta C mice differ from Ig alpha Delta C mice in that they show little impairment in early B cell development and they produce immature B cells that respond normally to BCR cross-linking as determined by Ca(2+) flux [18].
  • Analysis of Ig-alpha-tyrosine kinase interaction reveals two levels of binding specificity and tyrosine phosphorylated Ig-alpha stimulation of Fyn activity [19].
  • The nucleotide sequence of the m-mb-1 gene encodes a putative membrane glycoprotein with 220 amino acids, which includes a leader sequence, a putative extracellular domain with two potential N-glycosylation sites, a transmembrane portion and a putative intracellular domain [17].
  • In addition, these data indicate that the hydroxyl groups of the mutated residues are not required for functional association between mu and Ig-alpha/Ig-beta because their removal did not reduce the ability of the YS/FA mutant mIgM to associate with accessory proteins or to participate in signal transduction [20].
  • As expected, however, PTPs modulate the phosphorylation state of these proteins since another PTP inhibitor, phenylarsine oxide (PAO), increased phosphorylation of Ig-alpha, Ig-beta and other proteins in this system [21].

Physical interactions of Cd79a

  • In vivo, Id proteins modulate the transcriptional activity mediated by Pax-5 complexes on the B-cell-specific mb-1 promoter [22].

Enzymatic interactions of Cd79a

  • Syk protein-tyrosine kinase is regulated by tyrosine-phosphorylated Ig alpha/Ig beta immunoreceptor tyrosine activation motif binding and autophosphorylation [23].
  • Consistent with the proposed role for src family tyrosine kinases in AgR signaling, we found that Lck could phosphorylate the cytoplasmic tails of the Ig-alpha and Ig-beta components of the B cell AgR in vitro [24].

Regulatory relationships of Cd79a


Other interactions of Cd79a

  • Early B cell factor cooperates with Runx1 and mediates epigenetic changes associated with mb-1 transcription [1].
  • EBF and the basic helix-loop-helix transcription factor E47 each contributed to epigenetic modifications of the mb-1 promoter, including CpG demethylation and nucleosomal remodeling [1].
  • Although lambda5 and Ig-alpha are not expressed, the mu 0 and I mu transcripts from the unrearranged IgH locus are expressed early, in distinct patterns, then repressed just before RAG1 expression [26].
  • The promoter region lacks a TATA element, but contains two copies of an early B cell factor-binding motif, which previously has been shown to be important for murine mb-1 expression [27].
  • The mb-1 gene encodes the Ig-alpha component of the B-cell antigen receptor [28].

Analytical, diagnostic and therapeutic context of Cd79a


  1. Early B cell factor cooperates with Runx1 and mediates epigenetic changes associated with mb-1 transcription. Maier, H., Ostraat, R., Gao, H., Fields, S., Shinton, S.A., Medina, K.L., Ikawa, T., Murre, C., Singh, H., Hardy, R.R., Hagman, J. Nat. Immunol. (2004) [Pubmed]
  2. Cross-linking of the IgM receptor induces rapid translocation of IgM-associated Ig alpha, Lyn, and Syk tyrosine kinases to the membrane skeleton. Jugloff, L.S., Jongstra-Bilen, J. J. Immunol. (1997) [Pubmed]
  3. Down-regulation of membrane immunoglobulin-associated proteins, MB-1, B29 and Lyn, in AIDS-lymphomas and related conditions. Mori, S., Takanashi, M., Shiota, M., Choi, S.H., Yamanashi, Y., Watanabe, T., Koike, M. Virchows Arch. (1994) [Pubmed]
  4. The expression of the B-cell marker mb-1 (CD79a) in Hodgkin's disease. Korkolopoulou, P., Cordell, J., Jones, M., Kaklamanis, L., Tsenga, A., Gatter, K.C., Mason, D.Y. Histopathology (1994) [Pubmed]
  5. Properties of anti-idiotypic T cell lines propagated with syngeneic B lymphocytes. I. T cells bind intact idiotypes and discriminate between the somatic idiotypic variants in a manner similar to the anti-idiotopic antibodies. Cerny, J., Smith, J.S., Webb, C., Tucker, P.W. J. Immunol. (1988) [Pubmed]
  6. Failure of B-cell differentiation in mice lacking the transcription factor EBF. Lin, H., Grosschedl, R. Nature (1995) [Pubmed]
  7. A 13-amino-acid motif in the cytoplasmic domain of Fc gamma RIIB modulates B-cell receptor signalling. Muta, T., Kurosaki, T., Misulovin, Z., Sanchez, M., Nussenzweig, M.C., Ravetch, J.V. Nature (1994) [Pubmed]
  8. Molecular components of the B-cell antigen receptor complex of the IgM class. Hombach, J., Tsubata, T., Leclercq, L., Stappert, H., Reth, M. Nature (1990) [Pubmed]
  9. TCR-induced transmembrane signaling by peptide/MHC class II via associated Ig-alpha/beta dimers. Lang, P., Stolpa, J.C., Freiberg, B.A., Crawford, F., Kappler, J., Kupfer, A., Cambier, J.C. Science (2001) [Pubmed]
  10. Immunoglobulin mu heavy chains do not mediate tyrosine phosphorylation of Ig alpha from the ER-cis-Golgi. Mielenz, D., Ruschel, A., Vettermann, C., Jäck, H.M. J. Immunol. (2003) [Pubmed]
  11. Identification of BSAP (Pax-5) target genes in early B-cell development by loss- and gain-of-function experiments. Nutt, S.L., Morrison, A.M., Dörfler, P., Rolink, A., Busslinger, M. EMBO J. (1998) [Pubmed]
  12. Early B-cell factor, E2A, and Pax-5 cooperate to activate the early B cell-specific mb-1 promoter. Sigvardsson, M., Clark, D.R., Fitzsimmons, D., Doyle, M., Akerblad, P., Breslin, T., Bilke, S., Li, R., Yeamans, C., Zhang, G., Hagman, J. Mol. Cell. Biol. (2002) [Pubmed]
  13. Activation of the early B-cell-specific mb-1 (Ig-alpha) gene by Pax-5 is dependent on an unmethylated Ets binding site. Maier, H., Colbert, J., Fitzsimmons, D., Clark, D.R., Hagman, J. Mol. Cell. Biol. (2003) [Pubmed]
  14. Signaling-defective mutants of the B lymphocyte antigen receptor fail to associate with Ig-alpha and Ig-beta/gamma. Grupp, S.A., Campbell, K., Mitchell, R.N., Cambier, J.C., Abbas, A.K. J. Biol. Chem. (1993) [Pubmed]
  15. The Ig alpha/Igbeta heterodimer on mu-negative proB cells is competent for transducing signals to induce early B cell differentiation. Nagata, K., Nakamura, T., Kitamura, F., Kuramochi, S., Taki, S., Campbell, K.S., Karasuyama, H. Immunity (1997) [Pubmed]
  16. Ig alpha/Ig beta complexes generate signals for B cell development independent of selective plasma membrane compartmentalization. Fuentes-Pananá, E.M., Bannish, G., van der Voort, D., King, L.B., Monroe, J.G. J. Immunol. (2005) [Pubmed]
  17. B lymphocyte lineage-restricted expression of mb-1, a gene with CD3-like structural properties. Sakaguchi, N., Kashiwamura, S., Kimoto, M., Thalmann, P., Melchers, F. EMBO J. (1988) [Pubmed]
  18. B cell development is arrested at the immature B cell stage in mice carrying a mutation in the cytoplasmic domain of immunoglobulin beta. Reichlin, A., Hu, Y., Meffre, E., Nagaoka, H., Gong, S., Kraus, M., Rajewsky, K., Nussenzweig, M.C. J. Exp. Med. (2001) [Pubmed]
  19. Analysis of Ig-alpha-tyrosine kinase interaction reveals two levels of binding specificity and tyrosine phosphorylated Ig-alpha stimulation of Fyn activity. Clark, M.R., Johnson, S.A., Cambier, J.C. EMBO J. (1994) [Pubmed]
  20. A mutation of the mu transmembrane that disrupts endoplasmic reticulum retention. Effects on association with accessory proteins and signal transduction. Stevens, T.L., Blum, J.H., Foy, S.P., Matsuuchi, L., DeFranco, A.L. J. Immunol. (1994) [Pubmed]
  21. Manipulation of B cell antigen receptor tyrosine phosphorylation using aluminum fluoride and sodium orthovanadate. Campbell, K.S., Bedzyk, W.D., Cambier, J.C. Mol. Immunol. (1995) [Pubmed]
  22. Id helix-loop-helix proteins antagonize pax transcription factor activity by inhibiting DNA binding. Roberts, E.C., Deed, R.W., Inoue, T., Norton, J.D., Sharrocks, A.D. Mol. Cell. Biol. (2001) [Pubmed]
  23. Syk protein-tyrosine kinase is regulated by tyrosine-phosphorylated Ig alpha/Ig beta immunoreceptor tyrosine activation motif binding and autophosphorylation. Rowley, R.B., Burkhardt, A.L., Chao, H.G., Matsueda, G.R., Bolen, J.B. J. Biol. Chem. (1995) [Pubmed]
  24. Activation and serine phosphorylation of the p56lck protein tyrosine kinase in response to antigen receptor cross-linking in B lymphocytes. Gold, M.R., Chiu, R., Ingham, R.J., Saxton, T.M., van Oostveen, I., Watts, J.D., Affolter, M., Aebersold, R. J. Immunol. (1994) [Pubmed]
  25. An essential octamer motif in the mb-1 (Igalpha) promoter. Malone, C.S., Patrone, L., Wall, R. Mol. Immunol. (2000) [Pubmed]
  26. Cross-lineage expression of Ig-beta (B29) in thymocytes: positive and negative gene regulation to establish T cell identity. Wang, H., Diamond, R.A., Rothenberg, E.V. Proc. Natl. Acad. Sci. U.S.A. (1998) [Pubmed]
  27. Structure, chromosomal localization, and methylation pattern of the human mb-1 gene. Ha, H., Barnoski, B.L., Sun, L., Emanuel, B.S., Burrows, P.D. J. Immunol. (1994) [Pubmed]
  28. Regulatory elements of the mb-1 gene encoding the Ig-alpha component of the human B-cell antigen receptor. Leduc, I., Cogne, M. Mol. Immunol. (1996) [Pubmed]
  29. Cross-linking of B cell receptor-related MB-1 molecule induces protein tyrosine phosphorylation in early B lineage cells. Matsuo, T., Nomura, J., Kuwahara, K., Igarashi, H., Inui, S., Hamaguchi, M., Kimoto, M., Sakaguchi, N. J. Immunol. (1993) [Pubmed]
  30. Structure of the murine mb-1 gene encoding a putative sIgM-associated molecule. Kashiwamura, S., Koyama, T., Matsuo, T., Steinmetz, M., Kimoto, M., Sakaguchi, N. J. Immunol. (1990) [Pubmed]
  31. A human early B-cell factor-like protein participates in the regulation of the human CD19 promoter. Gisler, R., Akerblad, P., Sigvardsson, M. Mol. Immunol. (1999) [Pubmed]
  32. Regulation of an early developmental checkpoint in the B cell pathway by Ig beta. Gong, S., Nussenzweig, M.C. Science (1996) [Pubmed]
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