NF-kB activation and function in B lymphocytes

National Institute On Aging

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Abstract

Progress during FY18: 1) Completed and submitted for publication an analysis of NF-B target genes in PMA plus calcium ionophore-activated BJAB, a human B lymphoma cell line. We identified approximately 300 target genes that were up-regulated by NF-B. These genes had different kinetic patterns of activation, and we provided plausible mechanisms by which these patterns were generated. We also identified approximately 500 genes whose induction required NF-B, but which did not bind the transcription factor. We termed these indirect targets of NF-B that were activated by NF-B-induced transcription factors. A manuscript describing these observations is in press in PLOS Biology. 2) We used the pipeline established by the BJAB studies to query primary murine B lymphocytes for NF-B target genes regulated by signals from the B cell antigen receptor (BCR) or Toll-like receptor 4 (TLR4). This analysis will likely provide insights into mechanisms that establish stimulus-specificity of transcription responses, because both BCR and TLR4 activate NF-B but induce distinct gene regulatory outcomes. 3) We used Rel-deficient murine B lymphocytes in combined transcriptional and ChIP-Seq studies to understand the molecular basis for subunit-specific NF-B responses (in this case a comparison of Rel- and RelA-dependent gene expression). 4) Generation of conditional Gtf2ifL mice: - Gtf2ifL mice were bred to BL6 mice for 10 generations and named Gtf2ifL(G10B6). After the 10th generation they were breed to each other to have the fl/fl as HO (homozygous) (done before October 01, 2015). - Gtf2ifL(G10B6) were bred to the B-cell specific CD19cre, the pups were named Gtf2ifLxCD19-Cre. All litters of this strain were either Gtf2ifL Ht/CD19-Cre+ or Ht/CD19-Cre-. (Htheterozygous) - Gtf2ifLxCD19-Cre Ht/Cre+ were bred with Gtf2ifLxCD19-Cre Ht/Cre-, two breeding pairs of these mice gave 3 litters. - 6 pairs of Gtf2ifL Ht/CD19-Cre+ were bred to Gtf2ifL(G10B6) HO, one litter of 4 pups was weaned. Several pups exhibited correct genotype and were subsequently used for the following experiments. - ATAC- and RNA-Seq experiments were carried out, data analysis is in progress. Preliminary results show an interesting effect of ATF3 up-regulation in marginal zone B cells from Gtf2i-/-/ mice.