Expression and function of TRAF-3 splice-variant isoforms in human lymphoma cell lines.
TRAF-3 gene products are signaling adaptor molecules required for lymphocytes to mediate T-dependent antibody responses in vivo. Previous work identified 8 splice-variant TRAF-3 mRNA species by RT-PCR that have the potential to encode novel isoforms, seven of which induce NF-kappaB activation when over-expressed in 293 cells. Here, their expression was characterized by RNAse protection assay, which showed the T cell line Jurkat D1.1 and the B cell lines BJAB, Daudi, and Raji each expressed mRNA encoding TRAF-3 splice-variants in approximately the same rank order (from highest to lowest); TRAF-3 Delta103aa, Delta83aa, full-length, Delta25aa, Delta52aa, Delta56aa, Delta27aa, and Delta221aa mRNA. The TRAF-3 Delta130aa mRNA was not detectable in any of the cell lines examined. The functional effect of over-expressing each TRAF-3 splice-variant on NF-kappaB activation was studied in the TRAF-5-responsive B cell line, BJAB. Of the seven TRAF-3 splice-variant isoforms that induce NF-kappaB activation in 293 cells, only TRAF-3 Delta27aa, Delta103aa, or Delta130aa induce NF-kappaB activation in BJAB cells. Together, these data indicate that a number of TRAF-3 splice-variant mRNAs are expressed and function in B and T lymphoma lines, which suggests that certain TRAF-3 splice-variant isoforms may participate in mediating the known functions of the TRAF-3 gene in lymphocytes.
Gamper
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Laboratory of Molecular Immunology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
Omene
C O
CO
van Eyndhoven
W G
WG
Glassman
G D
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Lederman
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S
D017398:Alternative Splicing / Q000276:immunology*; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology; D017930:Genes, Reporter / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D016399:Lymphoma, T-Cell / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D011506:Proteins / Q000235:genetics* / Q000502:physiology; D012260:Ribonucleases / Q000378:metabolism; D017384:Sequence Deletion / Q000276:immunology; D048008:TNF Receptor-Associated Factor 3; D014162:Transfection; D014407:Tumor Cells, Cultured
D016328:NF-kappa B; D020033:Protein Isoforms; D011506:Proteins; D048008:TNF Receptor-Associated Factor 3; D012260:Ribonucleases