Local Genomic Features Predict the Distinct and Overlapping Binding Patterns of the bHLH‐Zip Family Oncoproteins MITF and MYC‐MAX
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PROVIDER: PRJNA476295 | ENA |
REPOSITORIES: ENA
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Project description:MITF and MYC are well‐known oncoproteins and members of the basic helix‐loop‐helix leucine zipper (bHLH‐Zip) family of transcription factors (TFs) recognizing hexamer E‐box motifs. MITF and MYC not only share the core binding motif, but are also the two most highly expressed bHLH‐Zip transcription factors in melanocytes, raising the possibility that they may compete for the same binding sites in select oncogenic targets. Mechanisms determining the distinct and potentially overlapping binding modes of these critical oncoproteins remain uncharacterized. We introduce computational predictive models using local sequence features, including a boosted convolutional decision tree framework, to distinguish MITF vs. MYC‐MAX binding sites with up to 80% accuracy genome wide. Select E‐box locations that can be bound by both MITF and MYC‐MAX form a separate class of MITF binding sites characterized by differential sequence content in the flanking region, diminished interaction with SOX10, higher evolutionary conservation, and less tissue‐specific chromatin organization.
2018-12-14 | GSE115845 | GEO
Project description:MITF and MYC are well-known oncoproteins and members of the basic helix-loop-helix leucine zipper (bHLH-Zip) family of transcription factors (TFs) recognizing hexamer E-box motifs. MITF and MYC not only share the core binding motif, but are also the two most highly expressed bHLH-Zip transcription factors in melanocytes, raising the possibility that they may compete for the same binding sites in select oncogenic targets. Mechanisms determining the distinct and potentially overlapping binding modes of these critical oncoproteins remain uncharacterized. We introduce computational predictive models using local sequence features, including a boosted convolutional decision tree framework, to distinguish MITF versus MYC-MAX binding sites with up to 80% accuracy genomewide. Select E-box locations that can be bound by both MITF and MYC-MAX form a separate class of MITF binding sites characterized by differential sequence content in the flanking region, diminished interaction with SOX10, higher evolutionary conservation, and less tissue-specific chromatin organization.
| S-EPMC6555698 | biostudies-literature
Project description:Microphthalmia-associated transcription factor (MITF) is a member of the basic helix-loop-helix leucine zipper (bHLH-Zip) family and functions as the master regulator of the melanocytic lineage. MITF-M is the predominant isoform expressed in melanocytes and melanoma cells, and, unlike other MITF isoforms, it is constitutively nuclear. Mutational analysis revealed three karyophilic signals in the bHLH-Zip domain of MITF-M, spanning residues 197-206, 214-217, and 255-265. Structural characterization of the MITF protein showed that basic residues within these signals are exposed for interactions in the absence of DNA. Moreover, our data indicate that neither DNA binding nor dimerization of MITF-M are required for its nuclear localization. Finally, dimerization-deficient MITF-M mutants exhibited a significantly reduced stability in melanoma cells when compared to the wild-type protein. Taken together, we have shown that, in addition to its well-established role in DNA binding and dimer formation, the bHLH-Zip domain of MITF modulates the transcription factor's subcellular localization and stability.
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Project description:Functional genomics identify distinct and overlapping genes mediating resistance to different classes of heterobifunctional degraders of oncoproteins
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Project description:Heterobifunctional proteolysis-targeting chimeric compounds leverage the activity of E3 ligases to induce degradation of target oncoproteins and exhibit potent preclinical antitumor activity. To dissect the mechanisms regulating tumor cell sensitivity to different classes of pharmacological "degraders" of oncoproteins, we performed genome-scale CRISPR/Cas9-based gene-editing studies. We observed that myeloma cell resistance to "degraders" of different targets (BET bromodomain proteins, CDK9) and operating through CRBN (degronimids) or VHL is primarily mediated by prevention of, rather than adaptation to, breakdown of the target oncoprotein; involves loss-of-function for the cognate E3 ligase or interactors/regulators of the respective cullin-RING ligase (CRL) complex. The substantial gene-level differences for CRBN- vs. VHL-based degraders explains mechanistically the lack of cross-resistance for degraders targeting the same protein via different E3 ligase/CRLs.
2021-02-12 | GSE162205 | GEO
Project description:The MITF-low melanoma transcriptional signature is predictive of poor outcome for patients but little is known about its biological signature. We used genetic models of zebrafish with low expression of mitfa (MITF-low) to study this biological subtype. We performed whole bulk RNA-seq to classify zebrafish MITF-low melanoma that cluster mainly by their directionality of growth and assess their resemblance to patients’ MITF-low subgroups. Furthermore, using genetic inhibition of MITF activity we discover minimal residual disease at the site of regression and using single-cell and low input RNA-seq we characterise these MITF independent cells and show that they pre-exist in the primary tumour.
2019-10-09 | GSE130037 | GEO
Project description:Great efforts have been made to identify key molecular aberrations that sustain growth and confer resistance to androgen deprivation therapy (ADT) in advanced prostate cancer (PC), and yet PC remains a lethal disease. Recent years have witnessed the discovery of several master regulator transcription factors that enhance lethal PC aggressiveness and provide actionable targets that may improve patient survival. Here we explore the role of the microphthalmia transcription factor (MITF) in lethal prostate cancer. To identify the mechanisms through which MITF mododulates prostate cancer aggressiveness, we knock-down MITF in three prostate cancer cell lines to identify the MITF regulated effector gene network contributing to lethal prostate cancer. Methods: We compared global transcription of three prostate cancer cell lines transduced with a siRNA control and 2 siRNAs targetting MITF by RNAseq. Results: RNA-seq of MITF knockdown prostate cancer cells uncovered a trasncriptional network of MITF regulated genes Conclusions: MITF regulates a discrette gene network that contributes to prostate cancer aggressiveness
2023-12-22 | GSE133977 | GEO
Project description:We evaluated two matched human cell lines derived from primary melanocytes, termed pmel+BRAF(V600E) and pmel+BRAF(V600E)+MITF. These cells are therefore isogenic with the exception of the expression of MITF. Gene Set Enrichment Analysis of microarray data identified a highly significant induction of oxidative phosphorylation gene set in MITF expressing cells compared to control cells.
2013-03-07 | E-GEOD-38007 | biostudies-arrayexpress
Project description:The MITF-low melanoma transcriptional signature is predictive of poor outcome for patients but little is known about its biological signature. We used genetic models of zebrafish with low expression of mitfa (MITF-low) to study this biological subtype. Using genetic inhibition of MITF activity we discover minimal residual disease at the site of regression. We performed single cell RNA-seq (Smart-seq2) to characterise cells at the site of residual disease, and put in relation with primary tumours and recurring disease.
2019-10-09 | GSE136900 | GEO
Project description:Cutaneous melanoma (CM) and uveal melanoma (UM) both originate from the melanocytic lineage but are primarily driven by distinct oncogenic drivers, BRAF/NRAS or GNAQ/GNA11 respectively. The melanocytic master transcriptional regulator, MITF, is essential for both CM development and maintenance, but its role in UM is largely unexplored. Here, we use zebrafish models to dissect the key UM oncogenic signaling events, and establish the role of MITF in UM tumors. Remarkably, mitfa deficiency was profoundly UM promoting, dramatically accelerating the onset and progression of tumors induced by Tg(mitfa:GNAQQ209L);tp53M214K/M214K. To further explore the role of MITF in GNAQ-driven tumorigenesis, we performed phospho-proteomics and total proteomics on 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K tumors and 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K;mitfa-/- tumors.
2023-03-11 | PXD030527 | Pride