Project description:We report the application of ChIP-Seq for high-throughput profiling of NFKB1/p50 binding dynamics. The binding profiles were performed under three conditions/models. We first examine the p50 binding in HEK293T cells during G1 and S phase. HEK293T cells were synchronized with double thymidine block method. Before and after release to S phase, ChIP was performed, and chromatin immunoprecipitated DNA was converted to libraries for sequencing with HiSeq 4000. We find that these NFKB1/p50 binding peaks in G1 phase dramatically reduced at S phase. Then, we further examine the p50 binding in HEK293T/TopBP1 cells in response to tamoxifen treatment. These cells have stable expression of TopBP1 activation domain fusion with estrogen receptor. After treatment, chromatin immunoprecipitated DNA was converted to libraries for sequencing with HiSeq 4000. We find that these NFKB1/p50 binding peaks in vehicle control sample dramatically reduced after tamoxifen treatment. Final, we compare the genome wide binding behavior of wild type p50 and mutant p50 2KR (K354R and K356R). HEK293T cells was transfected with plasmids expression HA-tagged wild type or mutation p50. Chromatin immunoprecipitated DNA was converted to libraries for sequencing with HiSeq 4000. We find that both wild type and p50 2KR mutant share similar binding profile. However, in general, p50 mutant has less binding affinity to NFKB binding sites. This study provides a preliminary but solid basis to our understanding of NFKB1/p50 binding dynamics.
Project description:Skeletal muscle atrophy is a debilitating condition associated with weakness, fatigue, and reduced functional capacity. Nuclear factor-kappaB (NF-κB) transcription factors play a critical role in atrophy. Knockout of genes encoding p50 or the NF-κB co-transactivator, Bcl-3, abolish disuse atrophy and thus they are NF-κB factors required for disuse atrophy. We do not know however, the genes targeted by NF-κB that produce the atrophied phenotype. Here we identify the genes required to produce disuse atrophy using gene expression profiling in wild type compared to Nfkb1 (gene encodes p50) and Bcl-3 deficient mice. There were 185 and 240 genes upregulated in wild type mice due to unloading, that were not upregulated in Nfkb1-/- and Bcl-3-/- mice, respectively, and so these genes were considered direct or indirect targets of p50 and Bcl-3. All of the p50 gene targets were contained in the Bcl-3 gene target list. Most genes were involved with protein degradation, signaling, translation, transcription, and transport. To identify direct targets of p50 and Bcl-3 we performed chromatin immunoprecipitation of selected genes previously shown to have roles in atrophy. Trim63 (MuRF1), Fbxo32 (MAFbx), Ubc, Ctsl, Runx1, Tnfrsf12a (Tweak receptor), and Cxcl10 (IP-10) showed increased Bcl-3 binding to κB sites in unloaded muscle and thus were direct targets of Bcl-3. p50 binding to the same sites on these genes either did not change or increased, supporting the idea of p50:Bcl-3 binding complexes. p65 binding to κB sites showed decreased or no binding to these genes with unloading. Fbxo9, Psma6, Psmc4, Psmg4, Foxo3, Ankrd1 (CARP), and Eif4ebp1 did not show changes in p65, p50, or Bcl-3 binding to κB sites, and so were considered indirect targets of p50 and Bcl-3. This work represents the first study to use a global approach to identify genes required to produce the atrophied phenotype with disuse. 24 mice were used based on 4 mice per group, 3 mouse genotypes (wild type, Nfkb1-/-, Bcl3-/-) and 2 conditions (weight-bearing and unloaded).
Project description:Background: Ozone (O3) is the predominant oxidant air pollutant associated with respiratory inflammation, lung dysfunction, and worsening preexisting airway diseases. We previously determined that lack of NF-kB signlaing pathway suppressed lung injury and inflammation caused by O3 in mice. The current study was to determine transcriptome mechanisms orchestrated by NF-kB during the development of pulmonary O3 injury. Methods: To investigate the role of NF-kB1 pathway in lung gene expression changes, Nfkb1-deficient (Nfkb1-/-) and wild-type (Nfkb1+/+) mice were exposed to air or 0.3-ppm O3. Total RNAs were isolated from lung homogenates and cDNA microarray analyses were performed to elucidate NF-kB1-directed transcriptomics in basal lungs (air-exposed) as well as in the lung exposed to O3 (48 hr). Results: In air-exposed Nfkb1-/- lungs, leukocyte extravasation/adhesion and antigen presentation genes were overexpressed while immunity genes were suppressed, supporting the dual role of Nf-kB1 homodimer as a transcriptional repressor as well as transcriptional activator and the phenotype of Nfkb1-/- mice (defective response to infection and specific antibody production). After O3 exposure. Nfkb1-/- mice showed suppressed expression of lung cell cycle genes and enhanced expression of DNA damage checkpoint regulation pathway genes, compared to Nfkb1+/+ mice. Conclusion: Overall, deficiency of NF-kB1 in mouse lungs altered transcriptomes to protect lungs from O3-induced inflammation, cell proliferation, and DNA damages.
Project description:Skeletal muscle atrophy is a debilitating condition associated with weakness, fatigue, and reduced functional capacity. Nuclear factor-kappaB (NF-κB) transcription factors play a critical role in atrophy. Knockout of genes encoding p50 or the NF-κB co-transactivator, Bcl-3, abolish disuse atrophy and thus they are NF-κB factors required for disuse atrophy. We do not know however, the genes targeted by NF-κB that produce the atrophied phenotype. Here we identify the genes required to produce disuse atrophy using gene expression profiling in wild type compared to Nfkb1 (gene encodes p50) and Bcl-3 deficient mice. There were 185 and 240 genes upregulated in wild type mice due to unloading, that were not upregulated in Nfkb1-/- and Bcl-3-/- mice, respectively, and so these genes were considered direct or indirect targets of p50 and Bcl-3. All of the p50 gene targets were contained in the Bcl-3 gene target list. Most genes were involved with protein degradation, signaling, translation, transcription, and transport. To identify direct targets of p50 and Bcl-3 we performed chromatin immunoprecipitation of selected genes previously shown to have roles in atrophy. Trim63 (MuRF1), Fbxo32 (MAFbx), Ubc, Ctsl, Runx1, Tnfrsf12a (Tweak receptor), and Cxcl10 (IP-10) showed increased Bcl-3 binding to κB sites in unloaded muscle and thus were direct targets of Bcl-3. p50 binding to the same sites on these genes either did not change or increased, supporting the idea of p50:Bcl-3 binding complexes. p65 binding to κB sites showed decreased or no binding to these genes with unloading. Fbxo9, Psma6, Psmc4, Psmg4, Foxo3, Ankrd1 (CARP), and Eif4ebp1 did not show changes in p65, p50, or Bcl-3 binding to κB sites, and so were considered indirect targets of p50 and Bcl-3. This work represents the first study to use a global approach to identify genes required to produce the atrophied phenotype with disuse.
Project description:To investigate the effects of NFKB signaling, RNA-seq analysis was performed on both Jurkat and MT-2 cells. It was observed that either NFKB1 or NFKB2 knockout could alter the gene expression profile in MT-2 cells compared to Jurkat cells. Gene expression profiles of NFKB1/NFKB2 knockout Jurkat cells were compared to the mock edited Jurkat cells. On the other hand, it was hypothesized that the gene expression profile of MT-2 cells can be more drastically altered by NFKB1 or NFKB2 knockout. NFKB2 knockout MT-2 cells exhibited a unique gene expression profile compared to those of NFKB1 knockout MT-2 cells and mock edited MT-2 cells.