Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. ChIP-Seq experiments for MYC-HA (HA-IP) performed in IMEC primary breast epithelial cells. Input-samples were sequenced as controlls.
Project description:YAP is an oncogene and an inducer of Epithelial-to-Mesenchymal Transition (EMT). We used microarrays to detail the global program of gene expression to identify YAP target genes. PUBLICATION ABSTRACT:; The Hippo pathway defines a novel signaling cascade regulating cell proliferation and survival in Drosophila, which involves the negative regulation of the transcriptional coactivator Yorkie by the kinases Hippo and Warts. We have recently shown that the human ortholog of Yorkie, YAP, maps to a minimal amplification locus in mouse and human cancers, and that it mediates dramatic transforming activity in MCF10A primary mammary epithelial cells. Here we show that LATS proteins (mammalian orthologs of Warts) interact directly with YAP in mammalian cells and that ectopic expression of LATS1, but not LATS2, effectively suppresses the YAP phenotypes. Furthermore, shRNA-mediated knockdown of LATS1 phenocopies YAP overexpression. Since this effect can be suppressed by simultaneous YAP knockdown, it suggests that YAP is the primary target of LATS1 in mammalian cells. Expression profiling of genes induced by ectopic expression of YAP or by knockdown of LATS1 reveals a subset of potential Hippo pathway targets implicated in epithelial-to-mesenchymal transition (EMT), suggesting that this is a key feature of YAP signaling in mammalian cells. Experiment Overall Design: MCF10A cells were infected with retrovirus constructs (vector or YAP) and puromycin was used to select for transduced cells. Cells were split and grown to ~60-75%% confluency at which point they were harvested for RNA. Vector vs. YAP comparison was done in duplicate.
Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. RNA-Seq Experiments in 2 different primary breast epithelial cell lines (HMLE, which were sorted according to CD44/CD24 surface markers & unsorted IMEC). Both cell lines expressed a doxycycline-inducible version of MYC. For the HMLE cell line DGE analysis was performed for the uninduced (EtOH) situation, comparing CD44high vs CD44 low and for the induced situation Dox vs. EtOH for the CD44high population. For the IMEC cell line DGE was performed by comparing Dox-treated populations expressing either Dox-inducible MYC or a vector control which allows to filter out potential effects due to doxycycline treatment.
Project description:TAZ, one of the key components of Hippo signaling pathway, is a transcription coactivator and plays an important role in cell proliferation, anti-apoptosis, therapeutic resistance, cancer stemness and tumorigenesis. TAZ mediated transcription program through transcription factors, such as TEAD family members. Genome-wide TAZ occupancy is poorly defined. Here, using a tet-inducible TAZ activation in mammary epithelial MCF10A cells, we characterized genome-wide binding sites in different TAZ activation time points. We found vast majority of TAZ binds to distal enhancer and intergenic regions of genes in the early TAZ activation time point and shift to promoter regions in the later TAZ activation time point. We identified three distinctive TAZ binding patterns to its targets. Furthermore, we found TAZ activation results in chromatin architecture alterations. Our studies provide insight of TAZ regulated transcription program in mammary epithelial cells and indicate potential therapeutic targets for breast cancer.
Project description:TAZ, one of the key components of Hippo signaling pathway, is a transcription coactivator and plays an important role in cell proliferation, anti-apoptosis, therapeutic resistance, cancer stemness and tumorigenesis. TAZ mediated transcription program through transcription factors, such as TEAD family members. Genome-wide TAZ occupancy is poorly defined. Here, using a tet-inducible TAZ activation in mammary epithelial MCF10A cells, we characterized genome-wide binding sites in different TAZ activation time points. We found vast majority of TAZ binds to distal enhancer and intergenic regions of genes in the early TAZ activation time point and shift to promoter regions in the later TAZ activation time point. We identified three distinctive TAZ binding patterns to its targets. Furthermore, we found TAZ activation results in chromatin architecture alterations. Our studies provide insight of TAZ regulated transcription program in mammary epithelial cells and indicate potential therapeutic targets for breast cancer.
Project description:TAZ, one of the key components of Hippo signaling pathway, is a transcription coactivator and plays an important role in cell proliferation, anti-apoptosis, therapeutic resistance, cancer stemness and tumorigenesis. TAZ mediated transcription program through transcription factors, such as TEAD family members. Genome-wide TAZ occupancy is poorly defined. Here, using a tet-inducible TAZ activation in mammary epithelial MCF10A cells, we characterized genome-wide binding sites in different TAZ activation time points. We found vast majority of TAZ binds to distal enhancer and intergenic regions of genes in the early TAZ activation time point and shift to promoter regions in the later TAZ activation time point. We identified three distinctive TAZ binding patterns to its targets. Furthermore, we found TAZ activation results in chromatin architecture alterations. Our studies provide insight of TAZ regulated transcription program in mammary epithelial cells and indicate potential therapeutic targets for breast cancer.
Project description:This study compares gene expression change upon expression of Yes-associated protein (YAP) wild-type or mutants in order to establish the importance of TEAD binding and WW domains in the gene-induction function of YAP. The results indicate that gene-induction is seriously comprised in YAP-S94A (TEAD binding domain mutant) expressing cells. And mutantion of WW domains (YAP-W1W2) also affect a fraction of YAP induced genes. Therefore both TEAD binding domain and WW domains are required for the full function of YAP in gene-induction. Experiment Overall Design: Four samples are included: 1. pQCXIH vector control; 2 YAP-WT expression; 3. YAP-S94A expression; 4. YAP-W1W2 expression. Gene expression profiles of YAP wild-type or mutants expressing cells were compared to that of vector control. Experiments were done in MCF10A mammary epithelial cells.
Project description:The optic vesicle comprises a pool of bi-potential progenitor cells from which the retinal pigment epithelium (RPE) and neural retina fates segregate during ocular morphogenesis. Several transcription factors and signaling pathways have been shown to be important for RPE maintenance and differentiation, but an understanding of the initial fate specification and determination of this ocular cell type is lacking. We show that Yap/Taz-Tead activity is necessary and sufficient for optic vesicle progenitors to adopt RPE identity in zebrafish. A Teadresponsive transgene is expressed within the domain of the optic cup from which RPE arises, and Yap immunoreactivity localizes to the nuclei of prospective RPE cells. yap (yap1) mutants lack a subset of RPE cells and/or exhibit coloboma. Loss of RPE in yap mutants is exacerbated in combination with taz (wwtr1) mutant alleles such that, when Yap and Taz are both absent, optic vesicle progenitor cells completely lose their ability to form RPE. The mechanism of Yap dependent RPE cell type determination is reliant on both nuclear localization of Yap and interaction with a Tead co-factor. In contrast to loss of Yap and Taz, overexpression of either protein within optic vesicle progenitors leads to ectopic pigmentation in a dosagedependent manner. Overall, this study identifies Yap and Taz as key early regulators of RPE genesis and provides a mechanistic framework for understanding the congenital ocular defects of Sveinsson’s chorioretinal atrophy and congenital retinal coloboma. 60 pooled eyes from 36 hpf wild type or vsx2:Gal4/dsRed:14xUAS:YapS87A embryos were pooled for one sample. Three wild type and three vsx2:Gal4/dsRed:14xUAS:YapS87A pools were analyzed for RNA.