Project description:Nuclear Factor Y (NF-Y) is a heterotrimeric transcription factor that binds CCAAT elements. The NF-Y trimer is composed of a Histone Fold Domain (HFD) dimer (NF-YB/NF-YC) and NF-YA, which confers DNA sequence specificity. NF-YA shares a conserved domain with the CONSTANS, CONSTANS-LIKE, TOC1 (CCT) proteins. We show that CONSTANS (CO/B-BOX PROTEIN1 BBX1), a master flowering regulator, forms a trimer with Arabidopsis thaliana NF-YB2/NF-YC3 to efficiently bind the CORE element of the FLOWERING LOCUS T promoter. Using saturation mutagenesis, electrophoretic mobility shift assays, and RNA-sequencing profiling of co, nf-yb, and nf-yc mutants, we identify CCACA elements as the core NF-CO binding site. CO physically interacts with the same HFD surface required for NF-YA association, as determined by mutations in NF-YB2 and NF-YC9, and tested in vitro and in vivo. The co-7 mutation in the CCT domain, corresponding to an NF-YA arginine directly involved in CCAAT recognition, abolishes NF-CO binding to DNA
Project description:Purpose: The purpose of this RNA Sequencing project was to investigate the transcriptional regulatory relationship between NF-YC3/4/9 and HY5 Methods: Total RNA was isolated, and then poly-A purified. 100ng of starting RNA was used to generate RNASeq libraries using the NEXTflex Illumina qRNA-Seq Library Prep Kit, and sequenced on an Illumina HiSeq2500 machine. Results: NF-YC3/4/9 and HY5 have both shared and independent regulatory targets.
Project description:Pro-inflammatory cytokines were shown to promote growth and survival of cancerous cells. TNF induced RelA:p50 NF-κB dimer via the canonical pathway is thought to link inflammation with cancer. Integrating biochemical and computational studies we identify that deficiency of non-canonical signal transducer p100 triggers a positive autoregulatory loop, which instead perpetuates an alternate RelB:p50 containing NF-κB activity upon TNF treatment. TNF stimulated RelB:p50 dimer is sufficient for mediating NF-κB target gene-expressions and suppressing apoptotic cellular death independent of principal NF-κB subunit RelA. We further demonstrate that activating mutations in non-canonical NF-κB module deplete multiple myeloma cells of p100, thereby, provoking autoregulatory RelB:p50 activation. Finally, autoregulatory control reinforces protracted pro-survival NF-κB response, albeit comprising of RelB:p50, upon TNF priming that protects myeloma cells with dysfunctional p100 from subsequent apoptotic insults. In sum, we present evidence for positive autoregulation mediated through the NF-κB system and its potential involvement in human neoplasm.
Project description:We provided an improved SELEX-Seq strategy for characterizing DNA-binding specificity of transcription factor. We valided the strategy by characterzing the DNA-binding specificty of NF-M-NM-:B p50 dimer. Proteins of the Nf-kappab family were bound to DNA oligonucleotides containing a degenerate region. The protein-DNA complexes were selected after one or multiple rounds of SELEX and the DNA molecules were deep sequenced.
Project description:Cell type-specific master transcription factors (MTFs) play vital roles in defining cell identity and function. However, the roles ubiquitous factors play in the specification of cell identity remain underappreciated. Here we show that all three subunits of the ubiquitous heterotrimeric CCAAT-binding NF-Y complex are required for the maintenance of embryonic stem cell (ESC) identity, and establish NF-Y as a novel component of the core pluripotency network. Genome-wide occupancy and transcriptomic analyses in ESCs and neurons reveal that not only does NF-Y regulate genes with housekeeping functions through cell type-invariant promoter-proximal binding, but also genes required for cell identity by binding to cell type-specific enhancers with MTFs. Mechanistically, NF-Y's distinctive DNA-binding mode promotes MTF binding at enhancers by facilitating a permissive chromatin conformation. Our studies unearth a novel function for NF-Y in promoting chromatin accessibility, and suggest that other proteins with analogous structural and DNA-binding properties may function in similar ways. Genome-wide mapping of NF-YA, NF-YB, and NF-YC subunits of the NF-Y complex in mouse ESCs, and microarray gene expression profiling of control knockdown (KD), NF-YA KD, NF-YB KD, NF-YC KD, and NF-YA/NF-YB/NF-YC triple KD ESCs.
Project description:Cell type-specific master transcription factors (MTFs) play vital roles in defining cell identity and function. However, the roles ubiquitous factors play in the specification of cell identity remain underappreciated. Here we show that all three subunits of the ubiquitous heterotrimeric CCAAT-binding NF-Y complex are required for the maintenance of embryonic stem cell (ESC) identity, and establish NF-Y as a novel component of the core pluripotency network. Genome-wide occupancy and transcriptomic analyses in ESCs and neurons reveal that not only does NF-Y regulate genes with housekeeping functions through cell type-invariant promoter-proximal binding, but also genes required for cell identity by binding to cell type-specific enhancers with MTFs. Mechanistically, NF-Y's distinctive DNA-binding mode promotes MTF binding at enhancers by facilitating a permissive chromatin conformation. Our studies unearth a novel function for NF-Y in promoting chromatin accessibility, and suggest that other proteins with analogous structural and DNA-binding properties may function in similar ways. Genome-wide mapping of NF-YA, NF-YB, and NF-YC subunits of the NF-Y complex in mouse ESCs, and microarray gene expression profiling of control knockdown (KD), NF-YA KD, NF-YB KD, NF-YC KD, and NF-YA/NF-YB/NF-YC triple KD ESCs.
Project description:We provided an improved SELEX-Seq strategy for characterizing DNA-binding specificity of transcription factor. We valided the strategy by characterzing the DNA-binding specificty of NF-κB p50 dimer.