Histone variant H2A.Z.2 primes MITF promoter to direct specification of melanocyte precursors
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ABSTRACT:
PROVIDER: PRJNA550083 | ENA |
REPOSITORIES: ENA
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Project description:Stem cell establishment and fate assignment are critical for both early development, as well as regeneration. A committed cell state is characterized by its unique transcriptional landscape. In contrast, the upstream fate-biased state is often metastable and transitory, thereby mechanisms of specification are difficult to identify. In this study, we elucidate the role of a histone variant H2a.z.2 in specification of melanocyte lineage from multipotent neural crest cells. Silencing of H2a.z.2 reduces the number of melanocyte precursors in developing zebrafish embryos, and from mouse embryonic stem cells in vitro. We demonstrate that this histone variant occupies nucleosomes in the promoter of key melanocyte determinant Mitf, and enhances its induction. CRISPR-Cas9 based targeted mutagenesis of this gene in zebrafish drastically reduces adult melanocytes, as well as their regeneration. Thereby our study establishes a histone based specification code upstream to the core gene regulatory network in the neural crest lineage leading to melanocytes. This epigenetic code renders the promoter of key determinant in a poised state conducive for activation by external instructive signals and facilitates establishment of downstream cell fate.
2020-03-05 | GSE133141 | 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: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: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 | GSE61966 | 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 | GSE61965 | GEO
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, “brown“ Tyrp1b/ b (melan-Ink4a-b) and “chocolate” 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
2009-05-04 | GSE10163 | GEO
Project description:The close integration of the MAPK, PI3K, and WNT signaling pathways underpins much of development and is deregulatedin cancer. In principle, combinatorial posttranslational modification of key lineage specific transcription factors would be an effective mean stointegrate critical signaling events. Understanding how this might be achieved is central to deciphering the impact of microenvironmental cues in development and disease. The microphthalmia-associated transcription factor MITF plays a crucial role in the development of melanocytes, the retinal pigment epithelium, osteoclasts, and mast cells and acts as a lineage survival oncogene in melanoma. MITF coordinates survival, differentiation, cell-cycle progression, cell migration, metabolism, and lysosome biogenesis. However, how the activity of this key transcriptionfactoriscontrolledremainspoorlyunderstood.Here,we showthatGSK3,downstreamfromboththePI3KandWntpathways, and BRAF/MAPK signaling converge to control MITF nuclear export. Phosphorylation of the melanocyte MITF-M isoform in response to BRAF/MAPK signaling primes for phosphorylation by GSK3, a kinase inhibited by both PI3K and Wnt signaling. Dual phosphorylation, but not monophosphorylation, then promotes MITF nuclear export by activatinga previously unrecognizedhydrophobic exportsignal. NonmelanocyteMITFisoformsexhibitpoorregulationbyMAPKsignaling, but instead their export is controlled by mTOR. We uncover here an unanticipated mode of MITF regulation that integrates the output of key developmental and cancer-associated signaling pathways to gate MITF flux through the import–export cycle. The results have significant implications for our understanding of melanoma progression and stem cell renewal.
2019-11-12 | PXD010782 | Pride
Project description:Thousands of enhancers are characterized in the human genome, yet few have been shown important in cancer. Inhibiting oncokinases, such as EGFR, ALK, HER2, and BRAF, is a mainstay of current cancer therapy but is hindered by innate drug resistance mediated by upregulation of the HGF receptor, MET. The mechanisms mediating such genomic responses to targeted therapy are unknown. Here, we identify lineage-specific MET enhancers for multiple common tumor types, including a melanoma lineage-specific MET enhancer that displays inducible chromatin looping and MET gene induction upon BRAF inhibition. Epigenomic analysis demonstrated that the melanocyte-specific transcription factor, MITF, mediates this enhancer function. Targeted genomic deletion (<7bp) of the MITF motif within the MET enhancer suppressed inducible chromatin looping and innate drug resistance, while maintaining MITF-dependent, inhibitor-induced melanoma cell differentiation. Epigenomic analysis can thus guide functional disruption of regulatory DNA to decouple pro- and anti-oncogenic functions of tumor lineage-enriched transcription factors mediating innate resistance to oncokinase therapy. MITF ChIP-seq was performed in primary human melanocytes with overexpression of BRAFV600E or a lentiviral control (RFP), and in COLO829 melanoma cells treated with DMSO, or PLX4032
2014-01-14 | E-GEOD-50681 | biostudies-arrayexpress