The chromatin dynamics of the TFAP2A/ MITF genetic interation in melanocyte development.
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PROVIDER: PRJNA787645 | ENA |
REPOSITORIES: ENA
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Project description:We have deleted TFAP2A and its redundantly-acting paralog TFAP2C in human melanoma SkMel28 cell lines and are assessing MITF binding using Cleavage Under Targets and Release Using Nuclease (CUT&RUN). Conversely, we deleted all copies of MITF in SkMEL28 cells and are similarly profiling TFAP2A bound loci. We predict TFAP2A functions as a pioneer factor for MITF during melanocyte development and that in the absence of TFAP2A, MITF binding at loci normally co-bound by MITF/TFAP2A will be disrupted.
2023-02-08 | GSE166359 | GEO
Project description:In developing melanocytes and in melanoma cells, multiple paralogs of the Activating-enhancer-binding Protein 2 family of transcription factors (TFAP2) contribute to expression of genes encoding pigmentation regulators, but their interaction with Microphthalmia transcription factor (MITF), a master regulator of these cells, is unclear. Supporting the model that Tfap2 facilitates MITF's ability to activate expression of pigmentation genes, single-cell seq analysis of zebrafish embryos revealed that pigmentation genes are only expressed in the subset of mitfa-expressing cells that also express Tfap2 paralogs. To test this model in SK-MEL-28 melanoma cells we deleted the two TFAP2 paralogs with highest expression, TFAP2A and TFAP2C, creating TFAP2 knockout (TFAP2-KO) cells. We then assessed gene expression, chromatin accessibility, binding of TFAP2A and of MITF, and the chromatin marks H3K27Ac and H3K27Me3 which are characteristic of active enhancers and silenced chromatin, respectively. Integrated analyses of these datasets indicate TFAP2 paralogs directly activate enhancers near genes enriched for roles in pigmentation and proliferation, and directly repress enhancers near genes enriched for roles in cell adhesion. Consistently, compared to WT cells, TFAP2-KO cells proliferate less and adhere to one another more. TFAP2 paralogs and MITF co-operatively activate a subset of enhancers, with the latter necessary for MITF binding and chromatin accessibility. By contrast, TFAP2 paralogs and MITF do not appear to co-operatively inhibit enhancers. These studies reveal a mechanism by which TFAP2 profoundly influences the set of genes activated by MITF, and thereby the phenotype of pigment cells and melanoma cells.
2022-04-26 | GSE190610 | GEO
Project description:Mutations in the gene encoding transcription factor TFAP2A result in pigmentation anomalies in model organisms and premature hair graying in humans. However, the pleiotropic functions of TFAP2A and its redundantly-acting paralogs have made the precise contribution of TFAP2-type activity to melanocyte differentiation unclear. Defining this contribution may help to explain why TFAP2A expression is reduced in advanced-stage melanoma compared to benign nevi. To identify genes with TFAP2A-dependent expression in melanocytes, we profile zebrafish tissue and mouse melanocytes deficient in Tfap2a, and find that expression of a small subset of genes underlying pigmentation phenotypes is TFAP2A-dependent, including Dct, Mc1r, Mlph, and Pmel. We then conduct TFAP2A ChIP-seq in mouse and human melanocytes and find that a much larger subset of pigmentation genes is associated with active regulatory elements bound by TFAP2A. These elements are also frequently bound by MITF, which is considered the “master regulator” of melanocyte development. For example, the promoter of TRPM1 is bound by both TFAP2A and MITF, and we show that the activity of a minimal TRPM1 promoter is lost upon deletion of the TFAP2A binding sites. However, the expression of Trpm1 is not TFAP2A-dependent, implying that additional TFAP2 paralogs function redundantly to drive melanocyte differentiation, which is consistent with previous results from zebrafish. Paralogs Tfap2a and Tfap2b are both expressed in mouse melanocytes, and we show that mouse embryos with Wnt1-Cre-mediated deletion of Tfap2a and Tfap2b in the neural crest almost completely lack melanocytes but retain neural crest-derived sensory ganglia. These results suggest that TFAP2 paralogs, like MITF, are also necessary for induction of the melanocyte lineage. Finally, we observe a genetic interaction between tfap2a and mitfa in zebrafish, but find that artificially elevating expression of tfap2a does not increase levels of melanin in mitfa hypomorphic or loss-of-function mutants. Collectively, these results show that TFAP2 paralogs, operating alongside lineage-specific transcription factors such as MITF, directly regulate effectors of terminal differentiation in melanocytes. In addition, they suggest that TFAP2A activity, like MITF activity, has the potential to modulate the phenotype of melanoma cells.
2017-02-23 | GSE67555 | GEO
Project description:Damage to the gene regulatory network governing terminal differentiation of melanocytes leads to pigmentation phenotypes and increases the risk for melanoma. Microphthalmia-associated transcription factor (MITF) directly activates expression of melanocyte differentiation effectors, and levels of MITF have been proposed to govern the melanoma phenotype. Mutations in the gene encoding Transcription Factor Activator Protein 2 alpha (TFAP2A) cause reduced pigmentation in model organisms and premature hair graying in humans, and TFAP2A expression tends to be lower in advanced melanoma tumors than in benign nevi. However, the transcriptional targets of TFAP2A in melanocytes, and the epistatic relationship of TFAP2A and MITF, have been unclear. Using microarray-based analysis of zebrafish tfap2a mutant embryos, we generated a profile of genes whose expression is Tfap2a-dependent. We conducted anti-TFAP2A chromatin immunoprecipitation followed by next-generation sequencing (ChIP-seq) in immortalized mouse melanocytes and human primary melanocytes, and discovered that TFAP2A peaks are present near the promoters of Tfap2a-dependent genes expressed in melanocytes, and also at the majority of enhancers active in melanocytes. Comparison of TFAP2A ChIP-seq data to published MITF ChIP-seq data showed that the set of genes with promoters bound by both MITF and TFAP2A is enriched for the gene ontology term “pigment cell differentiation.” Deletion analysis of one such co-bound promoter, for Transient Receptor Potential Melastatin-like 1(TRPM1), confirmed that its expression depends on the presence of MITF binding sites as previously shown, but also depends on the presence of TFAP2A binding sites. Finally, we find that mitfa and tfap2a interact genetically in zebrafish. Collectively, these results show that TFAP2A, operating in parallel with MITF, directly regulates effectors of terminal differentiation in melanocytes and melanoma.
2017-02-17 | GSE72953 | GEO
Project description:TFAP2A and MITF binding sites were identified in SK-MEL-28 cell lines using Cleavage Under Targets and Release Using Nuclease (CUT&RUN).
2021-02-08 | GSE153020 | GEO
Project description:Microphthalmia-associated transcription factor (MITF) is the master regulator of the melanocyte lineage. By tandem affinity purification and mass spectrometry, we present a comprehensive characterisation of the MITF interactome comprising multiple novel cofactors involved in transcription, DNA replication and repair and chromatin organisation, including a BRG1 chromatin remodelling complex comprising CHD7. BRG1 is essential for melanoma cell proliferation in vitro and for normal melanocyte development in vivo. MITF and SOX10 actively recruit BRG1 to a set of MITF-associated regulatory elements (MAREs) at active enhancers. MITF, SOX10 and YY1 bind between two BRG1-occupied nucleosomes thus defining both a combinatorial signature of transcription factors essential for the melanocyte lineage and a specific chromatin organisation of MAREs. Nevertheless, BRG1 silencing enhances MITF occupancy at MAREs showing that BRG1 acts to promote dynamic MITF interactions with chromatin. 8 samples corresponding to genomic occupancy profiling of MITF, SOX10, BRG1 after si-control, BRG1 after si-MITF and BRG1 after siSOX10; and their respective controls (MITF Input, SOX10 Input, GFP-siCTRL ChIPseq) in 501Mel cells.
2015-04-02 | E-GEOD-61965 | biostudies-arrayexpress
Project description:Microphthalmia-associated transcription factor (MITF) is the master regulator of the melanocyte lineage. By tandem affinity purification and mass spectrometry, we present a comprehensive characterisation of the MITF interactome comprising multiple novel cofactors involved in transcription, DNA replication and repair and chromatin organisation, including a BRG1 chromatin remodelling complex comprising CHD7. BRG1 is essential for melanoma cell proliferation in vitro and for normal melanocyte development in vivo. MITF and SOX10 actively recruit BRG1 to a set of MITF-associated regulatory elements (MAREs) at active enhancers. MITF, SOX10 and YY1 bind between two BRG1-occupied nucleosomes thus defining both a combinatorial signature of transcription factors essential for the melanocyte lineage and a specific chromatin organisation of MAREs. Nevertheless, BRG1 silencing enhances MITF occupancy at MAREs showing that BRG1 acts to promote dynamic MITF interactions with chromatin. 19 samples corresponding to mRNA profiles of 501Mel and Hermes3A after MITF, BRG1 or control shRNA-mediated knockdown were generated by deep sequencing in triplicate (in duplicate for 501_shMITF and corresponding control 501_shSCR2), using HiSeq2500.
2015-04-02 | E-GEOD-61966 | biostudies-arrayexpress
Project description:Gene expression profiling of tissues derived from different genetic backgrounds can provide insight to potential phenotype-related changes in gene expression. We have compared wildtype C57BL/6 (melan-Ink4a) melanocyte cell gene expression to that of, âbrownâ Tyrp1b/ b (melan-Ink4a-b) and âchocolateâ Rab38 cht/cht (melan-cht) melanocyte derived lines. We observed alterations in gene expression consistent with a physiological response of melan-Ink4a-b cells to endoplasmic reticulum protein-folding impairment. Additionally, a set of loci was identified that are expressed in a similar manner to known melanocyte genes. Importantly, the collection of 254 genes is enriched for expression in the multiple melanocyte lines relative to control cell populations. This set contains Tyr, Tyrp1, Dct, Si, Melna, Slc24a5, Slc45a2, Slc24a4, Mitf, and Sox10, in addition to genes not previously attributed to pigmentation and genes with unknown function. Further evaluation of one gene in this cohort, Gpnmb, demonstrated an expression pattern similar to Dct, Si and Mitf. This expression is vastly reduced in MitfMi mutants embryos, indicating that it is dependent on Mitf for in vivo expression. Consistent with this notion, a highly-conserved MITF binding site resides directly upstream of human GPNMB, and deletion of this sequence dramatically reduces in vitro enhancer activity. Keywords: NIH embryo fibroblast cell line, melanocyte cell line, Ink4a, Tyrp1b, Rab38 A 32k expression arrays were generated by printing Oligo nucleotides from Operon Mouse oligo set (MV3) onto epoxy slides. Total RNA from immortalized melanocyte cell lines derived from C57BL/6J Ink4a-/- (melan-Ink4a-1), C57BL/6J Ink4a-/-; Tyrp1b/b (melan-Ink4a-b) and 2 separate C57BL/6J Ink4a-/-; RaB38cht/cht lines (melan-cht4), (melan-cht5) and NIH3T3 were labeled with Cy5/3 and co-hybridized with a total RNA universal reference (Stratagene, Inc) labeled with Cy3/5. Each comparison was done in Triplicate including one dye swap.
2010-05-19 | E-GEOD-10163 | biostudies-arrayexpress
Project description:Microphthalmia-associated transcription factor (MITF) is the master regulator of the melanocyte lineage. By tandem affinity purification and mass spectrometry, we present a comprehensive characterisation of the MITF interactome comprising multiple novel cofactors involved in transcription, DNA replication and repair and chromatin organisation, including a BRG1 chromatin remodelling complex comprising CHD7. BRG1 is essential for melanoma cell proliferation in vitro and for normal melanocyte development in vivo. MITF and SOX10 actively recruit BRG1 to a set of MITF-associated regulatory elements (MAREs) at active enhancers. MITF, SOX10 and YY1 bind between two BRG1-occupied nucleosomes thus defining both a combinatorial signature of transcription factors essential for the melanocyte lineage and a specific chromatin organisation of MAREs. Nevertheless, BRG1 silencing enhances MITF occupancy at MAREs showing that BRG1 acts to promote dynamic MITF interactions with chromatin.
2015-04-02 | GSE61965 | GEO
Project description:Microphthalmia-associated transcription factor (MITF) is the master regulator of the melanocyte lineage. By tandem affinity purification and mass spectrometry, we present a comprehensive characterisation of the MITF interactome comprising multiple novel cofactors involved in transcription, DNA replication and repair and chromatin organisation, including a BRG1 chromatin remodelling complex comprising CHD7. BRG1 is essential for melanoma cell proliferation in vitro and for normal melanocyte development in vivo. MITF and SOX10 actively recruit BRG1 to a set of MITF-associated regulatory elements (MAREs) at active enhancers. MITF, SOX10 and YY1 bind between two BRG1-occupied nucleosomes thus defining both a combinatorial signature of transcription factors essential for the melanocyte lineage and a specific chromatin organisation of MAREs. Nevertheless, BRG1 silencing enhances MITF occupancy at MAREs showing that BRG1 acts to promote dynamic MITF interactions with chromatin.
2015-04-02 | GSE61966 | GEO