Project description:Using chromatin immunoprecipitation and high-resolution tiling arrays covering the human genome, we render a genome-wide map of p73 DNA binding sites in ME180 human cervical carcinoma cells.
Project description:The integral role of p53 in tumor suppression has promted many laboratories to perform extensive analyses of signaling pathways downstream of the p53 family of sequence-specific DNA binding transcription factors (p53 and its homologs p63 and p73). Despite the ability of p73 to regulate many p53 family target genes, little is known about the specific pathways that modulate p73 during development, tumorigenesis and tumor therapy. In this study we present a gene signature-based approach for connecting signaling pathways to transcription factors, as exemplified by p73. We generated a p73 gene signature by integrating whole-genome chromatin immunoprecipitation and expression profiling. Experiment Overall Design: H1299 lung carcinoma cells were infected with p73 expressing or control adenovirus for 5 h and then harvested.
Project description:The integral role of p53 in tumor suppression has promted many laboratories to perform extensive analyses of signaling pathways downstream of the p53 family of sequence-specific DNA binding transcription factors (p53 and its homologs p63 and p73). Despite the ability of p73 to regulate many p53 family target genes, little is known about the specific pathways that modulate p73 during development, tumorigenesis and tumor therapy. In this study we present a gene signature-based approach for connecting signaling pathways to transcription factors, as exemplified by p73. We generated a p73 gene signature by integrating whole-genome chromatin immunoprecipitation and expression profiling. Experiment Overall Design: H1299 lung carcinoma cells were transduced with TAp73beta or GFP expressing adenoviruses. Microarray analysis (on the GFP and TAp73beta samples) and ChIPSeq analysis (on the TAp73beta sample) were performed to identify candidate p73 target genes.
Project description:The p53-family member p73 functions in various cellular signaling pathways and can have tumor suppressor properties. Several isoforms of p73 exist that differ considerably in their function. Whereas the functions of the N-terminal isoforms (TA and M-NM-^TNp73) and their opposing pro- and anti-apoptotic roles became evident, the functional differences of the distinct C-terminal spliceforms of TAp73 have remained unclear. Here, we characterized the genomic binding sites for TAp73M-NM-1 and TAp73M-NM-2 and identified a specific p73 consensus binding-motif. Furthermore, an AP1 motif is strongly enriched close to binding sites for TAp73M-NM-1. These AP1 motif-containing target genes are selectively upregulated by TAp73M-NM-1, while their mRNA expression is repressed upon TAp73M-NM-2 induction. Recruitment of c-Jun to the respective AP1 sites was impaired upon TAp73M-NM-2 expression in part due to downregulation of c-Jun. We show that several of these AP1-site containing TAp73M-NM-1-induced genes reduce on apoptosis-induction suggesting an underlying molecular mechanism for the observed functional differences between TAp73M-NM-1 and TAp73M-NM-2. ChIP-seq and RNA-seq profiles of TAp73alpha, TAp73beta and p53 stably transfected in human osteosarcoma Saos cells
Project description:T helper (Th) cells play critical functions in response to infectious, allergic, and autoimmune diseases. Upon exposure to a given infectious agent or stimulus, different individuals vary in their Th cell responses, influencing the final disease outcome. To investigate the genetic factors that contribute to such differential immune responses, we performed a haplotype-based computational genetic analysis based on the phenotypic profiles of in vitro differentiated Th1 cells from 16 inbred mouse strains. And we identified genes including that encoding the p53 family protein, p73, with SNP patterns that correlated with the quantitative difference in IFNγ expression. Overexpression of p73 inhibited Th1 differentiation, as evaluated by reduced IFNγ expression, whereas shRNA knockdown or knockout of the p73 gene augmented IFNγ production. An inhibitory effect of p73 on Th1 differentiation was also observed in Stat1-/- cells, indicating that the effect was at least partially independent of STAT1. The DNA-binding activity of p73 is required for its inhibitory effect on IFNγ expression, as deletion of p73 DNA binding domain abolished IFNγ inhibition. A global gene expression analysis showed that 206 genes are differentially expressed more than two-fold in response to p73 overexpression, and 55 of these are direct target genes of p73 in Th1 cells, based on ChIP-seq analysis. p73 binding peaks were identified at a range of genes, including at the Il12rb2, Il24, and Il2ra loci, and p73 was implicated for regulating these genes based on reporter constructs containing WT or mutant p73 binding sites. Furthermore, p73 deficient mice had reduced disease severity in MOG induced EAE, with increased IFNg production from spinal cord infiltrating cells. Thus, p73 is a novel regulator of IFNγ expression, revealing a previously unanticipated role for p73 in Th1 cell differentiation.
Project description:The integral role of p53 in tumor suppression has promted many laboratories to perform extensive analyses of signaling pathways downstream of the p53 family of sequence-specific DNA binding transcription factors (p53 and its homologs p63 and p73). Despite the ability of p73 to regulate many p53 family target genes, little is known about the specific pathways that modulate p73 during development, tumorigenesis and tumor therapy. In this study we present a gene signature-based approach for connecting signaling pathways to transcription factors, as exemplified by p73. We generated a p73 gene signature by integrating whole-genome chromatin immunoprecipitation and expression profiling.
Project description:A central challenge in human cancer therapy is the identification of pathways that control tumor cell survival and chemosensitivity in the absence of functional p53. The p53-related transcription factors p63 and p73 exhibit distinct, p53-independent roles in development and cancer: p73 promotes genome stability and mediates chemosensitivity, while p63 largely lacks these p53-like functions and instead promotes proliferation and cell survival. Here, we identify a new and physiologically important mechanism of p63/p73 cross-talk which governs the balance between pro-survival and pro-apoptotic programs in both human and murine squamous cell carcinoma. Through comprehensive profiling of p63-regulated microRNAs (miRs), we identified a subset which target p73 for inhibition, including miR-193a-5p, a direct endogenous transcriptional target repressed by p63 and activated by pro-apoptotic p73 isoforms in both normal cells and tumor cells in vivo. Consequently, chemotherapy treatment causes p63/p73-dependent induction of this miR, thereby limiting chemosensitivity due to miR-mediated feedback control of p73. We demonstrate that interrupting this feedback by inhibiting miR-193a suppresses tumor cell viability and induces dramatic chemosensitivity both in vitro and in vivo. Thus, we have identified a direct, miR-dependent regulatory circuit mediating inducible chemoresistance, whose inhibition provides a new therapeutic opportunity in p53-deficient tumors. Knockdown of endogenous p63 by p63-directed or control lentiviral shRNA in JHU-029 human SCC cells at 48h, in duplicate experiments. Array analysis showing the fold-change and direction of change for all miRs regulated > 1.5-fold in p63-ablated versus control samples
Project description:The p53 family is known as a family of transcription factors with functions in tumor suppression and development. Whereas the central DNA binding domain is highly conserved among the three family members p53, p63 and p73, the C-terminal domains (CTDs) are diverse and subject to alternative splicing and post-translational modification. Here we demonstrate that the CTDs strongly influence DNA binding and transcriptional activity. While p53 and the p73 isoform p73ï§ have basic CTDs and form weak sequence-specific protein-DNA complexes, the major p73 isoforms ï¡, ï¢ and ï¤ have neutral CTDs and bind DNA strongly. A basic CTD has been previously shown to enable sliding along the DNA backbone and to facilitate the search for binding sites in the complex genome. Our experiments, however, reveal that a basic CTD also reduces protein-DNA complex stability, intranuclear mobility, promoter occupancy in vivo, transgene activation and induction of cell cycle arrest or apoptosis. A basic CTD in p53 and p73ï§ therefore provides both positive and negative regulatory functions presumably to enable rapid switching of protein activity in response to stress. In contrast, most p73 isoforms exhibit constitutive DNA binding activity consistent with a predominant role in developmental control. Experiment Overall Design: Infection of H1299 cell with different p73/p53 constructs by adenoviral system