Project description:Establishment and differentiation of mammary alveoli during pregnancy are controlled by prolactin through the transcription factor STAT5. As pregnancy progresses mammary signature genes are activated in a defined temporal order, which coincides with the recruitment of STAT5 to respective regulatory sequences. This study addressed the question whether the methyltransferase and transcriptional co-activator EZH2 controls the differentiation clock of mammary epithelium. Ablation of Ezh2 from mammary stem cells resulted in precocious differentiation of alveolar epithelium during pregnancy and the activation of mammary-specific STAT5 target genes. This coincided with enhanced occupancy by STAT5, EZH1 and Pol II to these loci. Limited activation of differentiation-specific genes was also observed in mammary epithelium lacking both EZH2 and STAT5, suggesting a modulating but not mandatory role for STAT5. Notably, loss of EZH2 did not result in overt changes in genome-wide and gene-specific H3K27me3 patterns, suggesting that enhanced EZH1 recruitment can compensate for the loss of EZH2. Differentiated mammary epithelia failed to form in the combined absence of EZH1 and EZH2. Transplantation experiments failed to demonstrate a role for EZH2 in the biology of mammary stem and progenitor cells. In summary, while EZH1 and EZH2 serve redundant functions in the establishment of H3K27me3 and formation of mammary alveoli, the presence of EZH2 is required to obtain controlled temporal differentiation of mammary epithelium. mRNA-seq in WT;MMTV-Cre (Control) at p13 and p18, E1-/- (E1KO), Ezh2f/f;MMTV-Cre(E2KO), Stat5f/f;MMTV-Cre(S5KO), and Ezh2f/f;Stat5f/f;MMTV-Cre (E2S5DKO) at p13 mammary tissues. ChIP-seq for H3K27me3, STAT5, EZH1, EZH2 and PolII in mammary tissues at p13
Project description:Establishment and differentiation of mammary alveoli during pregnancy are controlled by prolactin through the transcription factor STAT5. As pregnancy progresses mammary signature genes are activated in a defined temporal order, which coincides with the recruitment of STAT5 to respective regulatory sequences. This study addressed the question whether the methyltransferase and transcriptional co-activator EZH2 controls the differentiation clock of mammary epithelium. Ablation of Ezh2 from mammary stem cells resulted in precocious differentiation of alveolar epithelium and accelerated activation of mammary signature genes. This coincided with enhanced occupancy by EZH1, Pol II and STAT5 to mammary-specific loci. Notably, loss of EZH2 did not result in overt changes in genome-wide and gene-specific H3K27me3 patterns, suggesting that enhanced EZH1 recruitment can compensate for the loss of EZH2. However, differentiated mammary epithelia failed to form in the combined absence of EZH1 and EZH2. Transplantation experiments failed to demonstrate a role for EZH2 in the biology of mammary stem and progenitor cells. In summary, while EZH1 and EZH2 serve redundant functions in the establishment of H3K27me3 and formation of mammary alveoli, the presence of EZH2 is required to obtain controlled temporal differentiation of mammary epithelium. ChIP-seq EZH1, EZH2, PolIII; WT and E2KO mammary cells
Project description:Establishment and differentiation of mammary alveoli during pregnancy are controlled by prolactin through the transcription factor STAT5. As pregnancy progresses mammary signature genes are activated in a defined temporal order, which coincides with the recruitment of STAT5 to respective regulatory sequences. This study addressed the question whether the methyltransferase and transcriptional co-activator EZH2 controls the differentiation clock of mammary epithelium. Ablation of Ezh2 from mammary stem cells resulted in precocious differentiation of alveolar epithelium during pregnancy and the activation of mammary-specific STAT5 target genes. This coincided with enhanced occupancy by STAT5, EZH1 and Pol II to these loci. Limited activation of differentiation-specific genes was also observed in mammary epithelium lacking both EZH2 and STAT5, suggesting a modulating but not mandatory role for STAT5. Notably, loss of EZH2 did not result in overt changes in genome-wide and gene-specific H3K27me3 patterns, suggesting that enhanced EZH1 recruitment can compensate for the loss of EZH2. Differentiated mammary epithelia failed to form in the combined absence of EZH1 and EZH2. Transplantation experiments failed to demonstrate a role for EZH2 in the biology of mammary stem and progenitor cells. In summary, while EZH1 and EZH2 serve redundant functions in the establishment of H3K27me3 and formation of mammary alveoli, the presence of EZH2 is required to obtain controlled temporal differentiation of mammary epithelium.
Project description:Establishment and differentiation of mammary alveoli during pregnancy are controlled by prolactin through the transcription factor STAT5. As pregnancy progresses mammary signature genes are activated in a defined temporal order, which coincides with the recruitment of STAT5 to respective regulatory sequences. This study addressed the question whether the methyltransferase and transcriptional co-activator EZH2 controls the differentiation clock of mammary epithelium. Ablation of Ezh2 from mammary stem cells resulted in precocious differentiation of alveolar epithelium and accelerated activation of mammary signature genes. This coincided with enhanced occupancy by EZH1, Pol II and STAT5 to mammary-specific loci. Notably, loss of EZH2 did not result in overt changes in genome-wide and gene-specific H3K27me3 patterns, suggesting that enhanced EZH1 recruitment can compensate for the loss of EZH2. However, differentiated mammary epithelia failed to form in the combined absence of EZH1 and EZH2. Transplantation experiments failed to demonstrate a role for EZH2 in the biology of mammary stem and progenitor cells. In summary, while EZH1 and EZH2 serve redundant functions in the establishment of H3K27me3 and formation of mammary alveoli, the presence of EZH2 is required to obtain controlled temporal differentiation of mammary epithelium.
Project description:Cytokines control the expression of common and cell-specific genes through the transcription factor STAT5. In mammary tissue specifically, expression of approximately 570 genes is induced during pregnancy by prolactin through STAT5, which binds to putative regulatory sequences. We have now asked whether mammary-specific induction of these genes can be linked to the presence of additional transcription factors, which would act in concert with STAT5. RNA-seq analysis at parturition identified 370 genes that were under NFIB control. Notably, 75% of these genes, encoding proteins linked to the differentiation of mammary epithelium, were also regulated by STAT5. This study demonstrates that the STAT5-NFIB module is an essential part of genes that define differentiation and function of the mammary gland. Expression profiling by high throughput sequencing in wild-type (WT) and Nfib-null (KO) mammary gland tissues
Project description:Cytokines control the expression of common and cell-specific genes through the transcription factor STAT5. In mammary tissue specifically, expression of approximately 570 genes is induced during pregnancy by prolactin through STAT5, which binds to putative regulatory sequences. We have now asked whether mammary-specific induction of these genes can be linked to the presence of additional transcription factors, which would act in concert with STAT5. RNA-seq analysis at parturition identified 370 genes that were under NFIB control. Notably, 75% of these genes, encoding proteins linked to the differentiation of mammary epithelium, were also regulated by STAT5. This study demonstrates that the STAT5-NFIB module is an essential part of genes that define differentiation and function of the mammary gland.
Project description:Mammary development is characterized by the proliferation and progressive differentiation of alveolar epithelium during pregnancy, culminating in lactation. These processes are largely controlled by hormones through transcription factors. We now explore the contributions of histone methyltransferases, which establish H3K27me3 marks, in the temporally-regulated differentiation of mammary epithelium. Loss of EZH2, but not EZH1, resulted in precocious mammary differentiation, which was facilitated by STAT5 binding to specific target genes and their activation. Mammary stem cells were not compromised in the absence of EZH2. Genome-wide H3K27me3 patterns remained intact in the absence of EZH2. Mammary-specific loci were devoid of H3K27me3 marks in mammary progenitor and mature cells, suggesting no regulatory role for this repressive mark. Lastly, the combined absence of EZH1 and EZH2 inhibited the formation of alveoli. Taken together, EZH2 controls temporally-restricted differentiation of mammary epithelium through H3K27me3-independent mechanisms. mRNA-seq and ChIP-seq in MMTV-Cre (Control), E1-/- (E1KO), E1+/-;E2f/f;control (E1+/-E2KO) and Ezh2f/f;control (E2KO) mammary gland tissues or MECs (purified mammary epithelial cells). H3K27me3 and STAT5 ChIP-seqs in mammary tissues at p13; H3K4me3 ChIP-seq in MECs (mammary epithelial cells) at p13; RNA-seqs at mature virgin (with/without prolactin injection), p13 and p18 mammary tissues.
Project description:Mammary development is characterized by the proliferation and progressive differentiation of alveolar epithelium during pregnancy, culminating in lactation. These processes are largely controlled by hormones through transcription factors. We now explore the contributions of histone methyltransferases, which establish H3K27me3 marks, in the temporally-regulated differentiation of mammary epithelium. Loss of EZH2, but not EZH1, resulted in precocious mammary differentiation, which was facilitated by STAT5 binding to specific target genes and their activation. Mammary stem cells were not compromised in the absence of EZH2. Genome-wide H3K27me3 patterns remained intact in the absence of EZH2. Mammary-specific loci were devoid of H3K27me3 marks in mammary progenitor and mature cells, suggesting no regulatory role for this repressive mark. Lastly, the combined absence of EZH1 and EZH2 inhibited the formation of alveoli. Taken together, EZH2 controls temporally-restricted differentiation of mammary epithelium through H3K27me3-independent mechanisms.
Project description:Our study revealed that CUZD1 (CUB and zona pellucida-like domain containing protein-1) is a novel target of estrogen regulation in the mouse mammary epithelium. Mice lacking Cuzd1 exhibit delayed ductal outgrowth during puberty and a striking impairment in ductal branching and alveolar development during pregnancy. Ablation of Cuzd1 led to a marked reduction in steroid-induced proliferation of mammary ductal and alveolar epithelium. To identify the downstream targets of Cuzd1 in mammary gland development, we performed gene expression profling of mammary epithlial cells isolated from Cuzd1-null and its heterozygous litteremates on day 18 of pregnancy. The microarray results revealed downregulation of mRNAs corresponding to several members of the epidermal growth factor family in mammary epithelial cells of Cuzd1-null mice. Consequently, the activation of the ERBB receptors, ERBB1 and ERBB4, and their downstream target STAT5, was disrupted in Cuzd1-null mammary tissue. Collectively, these findings support a unique role for CUZD1 as a critical mediator of the steroid-induced proliferation and differentiation of ductal epithelium during pregnancy and lactation.
Project description:Our study revealed that CUZD1 (CUB and zona pellucida-like domain containing protein-1) is a novel target of estrogen regulation in the mouse mammary epithelium. Mice lacking Cuzd1 exhibit delayed ductal outgrowth during puberty and a striking impairment in ductal branching and alveolar development during pregnancy. Ablation of Cuzd1 led to a marked reduction in steroid-induced proliferation of mammary ductal and alveolar epithelium. To identify the downstream targets of Cuzd1 in mammary gland development, we performed gene expression profling of mammary epithlial cells isolated from Cuzd1-null and its heterozygous litteremates on day 18 of pregnancy. The microarray results revealed downregulation of mRNAs corresponding to several members of the epidermal growth factor family in mammary epithelial cells of Cuzd1-null mice. Consequently, the activation of the ERBB receptors, ERBB1 and ERBB4, and their downstream target STAT5, was disrupted in Cuzd1-null mammary tissue. Collectively, these findings support a unique role for CUZD1 as a critical mediator of the steroid-induced proliferation and differentiation of ductal epithelium during pregnancy and lactation. To investigate the functional role of Cuzd1, we created Cuzd1-null mice by homologous recombination using mouse embryonic stem cells. As severe defect was observed in alveolargenesis and lactation of Cuzd1 null mammary gland, we purified mammary epithlial cells from day18 pregnant mice (n=5 for each genotype), purified total RNA from these cells, pooled these samples and then hybridized to high density affymetrix microarrays.