Project description:We provided earlier evidence that acetylation of p65 at lysines 310, 314 and 315 is important for the expression of a defined subset of genes; acetylation at these residues regulates both positively and negatively gene expression, in a gene-specific manner. These earlier studies provided a first glance of the functional relevance of p65 acetylation, since gene expression was measured only after 45 minutes of TNFα stimulation. In order to know if the requirement for site-specific acetylation is maintained for the same genes after longer exposure to TNFα, and to identify possible new genes regulated through p65 acetylation, we decided to extent our analysis to 3 hours of stimulation. For this, we used p65(-/-) MEFs complemented with non-acetylatable mutants, where the target lysines for acetylation were mutated to arginines. p65(-/-) cells complemented either with wild type p65, an empty plasmid as control (pTV), the acetylation-deficient double mutant K314/315R or the triple mutant KTR (K310/314/315R), were stimulated by TNFα for 3 hours and total RNA was isolated in three independent replicates from these cells. RNA was amplified, labeled and hybridized to the Agilent Whole Mouse Genome Array. After statistical analysis of the expression profiles, differentially expressed genes were identified.
Project description:We provided earlier evidence that acetylation of p65 at lysines 310, 314 and 315 is important for the expression of a defined subset of genes; acetylation at these residues regulates both positively and negatively gene expression, in a gene-specific manner. These earlier studies provided a first glance of the functional relevance of p65 acetylation, since gene expression was measured only after 45 minutes of TNFα stimulation. In order to know if the requirement for site-specific acetylation is maintained for the same genes after longer exposure to TNFα, and to identify possible new genes regulated through p65 acetylation, we decided to extent our analysis to 3 hours of stimulation. For this, we used p65(-/-) MEFs complemented with non-acetylatable mutants, where the target lysines for acetylation were mutated to arginines.
Project description:LMX1B is a LIM-homeodomain transcription factor essential for development. Putative LMX1B target genes have been identified through mouse gene targeting studies; however, in the absence of in vivo molecular characterization of their regulation, their identity as direct LMX1B targets remains hypothetical. We describe here the first molecular characterization of LMX1B target gene regulation. A tetracycline-inducible expression system and microarray analysis showed that a subset of NF-kappa B target genes, including IL-6 and IL-8 are upregulated in LMX1B-expressing HeLa cells. Chromatin immunoprecipitation assays revealed that LMX1B binds to the proximal promoter region of IL-6 and IL-8 in vivo, in the vicinity of the characterized kappa B site, and that LMX1B recruitment correlates with an increased NF-kappa B DNA association. Inhibition of NF-kappa B activity by short interfering RNA-mediated knock-down of p65 impairs LMX1B-dependent induction of NF-kappa B target genes, while activation of NF-kappa B activity by TNF-alpha results in a synergistic induction of these genes by LMX1B. IL-6 promoter-driven reporter assays showed that the kappa B site and an adjacent putative LMX1B binding motif are both involved in LMX1B-mediated transcription. Expression of a number of NF-kappa B target genes is affected in the kidney of Lmx1b-/- knock-out mice, thus supporting the biological relevance of the data obtained in the human cell line. Together, these data demonstrate for the first time that LMX1B directly regulates transcription of a subset of NF-kappa B target genes in cooperation with nuclear p50/p65 NF-kappa B. Human subset (GSM303547-GSM303550): Two biological replicates of non-expressing HtTA-LMX1B cells (grown in doxycycline-containing medium) and of LMX1B-expressing HtTA-LMX1B cells (grown for 4 days in doxycycline-free medium) were processed for gene expression array analyses using an Affymetrix platform. Mouse subset (GSM304379-GSM304384): Three kidney samples from newborn wild-type mice and from newborn Lmx1b-/- knock-out mice were processed for gene expression array analyses using an Agilent platform.
Project description:In effort to develop methodology for targeted top down mass spectrometry of NF kappa B p65 from human cells, we evaluated the utility of HaloTag for purification and analysis of recombinant protein. During our study, two datasets of bottom up LC-MS/MS were generated: one from in-gel digestion of the predominant band following p65-HaloTag purification, another from in-solution digestion of all the proteins present in a p65-HaloTag purification. p65-HaloTag copurifying proteins identified in our datasets include the known interactors c-Rel, NF-kappaB p105, NF-kappaB p100, and NF-kappaB inhibitor beta. Over 100 proteins were identified by at least two peptides using a Mascot ion cut-off score of 30.
Project description:LMX1B is a LIM-homeodomain transcription factor essential for development. Putative LMX1B target genes have been identified through mouse gene targeting studies; however, in the absence of in vivo molecular characterization of their regulation, their identity as direct LMX1B targets remains hypothetical. We describe here the first molecular characterization of LMX1B target gene regulation. A tetracycline-inducible expression system and microarray analysis showed that a subset of NF-kappa B target genes, including IL-6 and IL-8 are upregulated in LMX1B-expressing HeLa cells. Chromatin immunoprecipitation assays revealed that LMX1B binds to the proximal promoter region of IL-6 and IL-8 in vivo, in the vicinity of the characterized kappa B site, and that LMX1B recruitment correlates with an increased NF-kappa B DNA association. Inhibition of NF-kappa B activity by short interfering RNA-mediated knock-down of p65 impairs LMX1B-dependent induction of NF-kappa B target genes, while activation of NF-kappa B activity by TNF-alpha results in a synergistic induction of these genes by LMX1B. IL-6 promoter-driven reporter assays showed that the kappa B site and an adjacent putative LMX1B binding motif are both involved in LMX1B-mediated transcription. Expression of a number of NF-kappa B target genes is affected in the kidney of Lmx1b-/- knock-out mice, thus supporting the biological relevance of the data obtained in the human cell line. Together, these data demonstrate for the first time that LMX1B directly regulates transcription of a subset of NF-kappa B target genes in cooperation with nuclear p50/p65 NF-kappa B.
Project description:Metastasis suppressor 1 (MTSS1) is a 755 amino acid protein found in the cell cytoplasm which binds to actin and promotes cytoskeleton organization and is a known suppressor of lung adenocarcinoma metastasis This study demonstrated that preservation of MTSS1 protein expression in lung adenocarcinoma was associated with a 20% 5-year survival advantage in patients. Furthermore, overexpression of MTSS1 was found to reduce metastasis and disease progression in an in-vivo orthotopic lung adenocarcinoma mouse model. Nuclear factor kappa B (NF-kB), an important nuclear transcription factor, has been shown to be constitutively active in lung adenocarcinoma and strongly associated with the development of metastasis. The NF-kB RelA/p65 subunit is involved in NF-kB heterodimer formation and subsequent nuclear translocation leading to activation of NF-kB responsive gene transcription. Phosphorylation and acetylation of p65 are critical post-translational modifications required for NF-kB activation. In this study, we demonstrate that MTSS1 expression leads to decreased NF-κB mediated gene transcription through inhibition of p65 phosphorylation. These findings uncover a novel mechanism through which MTSS1 may regulate lung adenocarcinoma metastasis by impairment of NF-κB regulated gene transcription.
Project description:Protein acetylation is a central event in orchestrating diverse cellular processes. However, current strategies to investigate protein acetylation in cells are often non-specific or lack temporal and magnitude control. Here, we developed an acetylation tagging system, AceTAG, to induce acetylation of targeted proteins. The AceTAG system utilizes bifunctional molecules to direct the lysine acetyltransferase p300/CBP to proteins fused with the small protein tag FKBP12F36V, resulting in their induced acetylation. Using AceTAG, we induced targeted acetylation of a diverse array of proteins in cells, specifically histone H3.3, the NF-B subunit p65/RelA, and the tumor suppressor p53. We demonstrate that targeted acetylation with the AceTAG system is rapid, selective, reversible, and can be controlled in a dose-dependent fashion. AceTAG represents a useful strategy to modulate protein acetylation and will enable the exploration of targeted acetylation in basic biological and therapeutic contexts.
Project description:We found genetic deletion of IKKβ in mdx cardiomyocytes improved cardiac function and normalized calcium transients, and that differential gene expression favored a repressive function for NF-[kappa]B in these mice. We suspected that NF-[kappa]B was conferring a more restrictive chromatin conformation in a subset of genes. ChIP-seq was performed for H3K27 acetylation to show this repressive function for NF-[kappa]B was a global effect and to identify specific genes with more permissive chromatin conformation in hearts of mdx mice with IKKβ-deficient cardiomyocytes compared to mdx mice with intact IKKβ signaling.
Project description:Activation of nuclear factor kappa B (NF-kB) by inflammatory signals results in nuclear translocation of the transcription factor p65 and induction of gene expression. We identified MED12 and MED24 in an optical pooled CRISPR knockout screen in HeLa-Cas9 cells for genes affecting the activation and/or relaxation of p65 to the cytoplasm following induction by either TNFa or IL-1b. We generated isogenic clonal knockout HeLa-Cas9 lines using crRNA transfection and confirmed that loss of MED12 or MED24 results in delayed relaxation of p65, assayed by live-cell imaging of a p65-mNeonGreen fluorescent fusion.