B cell receptor accessory molecules in the channel catfish, Ictalurus punctatus.
B cell receptor (BCR) accessory molecules CD79a and CD79b homologs were identified in the channel catfish, Ictalurus punctatus. Both are found as single copy genes that encode proteins containing a signal peptide, an extracellular immunoglobulin domain, a transmembrane region and a cytoplasmic tail containing an immune-receptor tyrosine-dased activation motif (ITAM). IpCD79a and IpCD79b transcripts correlate well with IgM message expression. They are highly expressed in peripheral blood leukocytes (PBL) enriched in membrane (m) IgM+ cells and catfish clonal B cell lines, but not in catfish clonal T cells, indicating that IpCD79a and IpCD79b expression is B cell restricted. Studies using catfish clonal B cells (3B11) transfected with constructs encoding epitope-tagged IpCD79a and IpCD79b revealed that IpCD79a was expressed as a 45 kDa protein and IpCD79b was expressed as a 32 kDa protein. Furthermore, co-immunoprecipitations of epitope-tagged CD79 proteins demonstrate that these molecules are non-covalently associated with mIgM. These data correlate with some of the previous immunoprecipitation data demonstrating that catfish mIgM associates with proteins of 45 and 32 kDa.
Sahoo
Manoranjan
M
Department of Microbiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA.
Edholm
Eva-Stina
ES
Stafford
James L
JL
Bengtén
Eva
E
Miller
Norman W
NW
Wilson
Melanie
M
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D051925:CD79 Antigens / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D002397:Catfishes / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation; D007075:Immunoglobulin M / Q000276:immunology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D051925:CD79 Antigens; D007075:Immunoglobulin M