Project description:POU1F1 regulates, in the pituitary, the development of the prolactin-, growth hormone- and thyrotropin ß-expressing lineages and the expression of these hormone in the mature pituitary through the direct regulation of their promoters. Besides these functions, POU1F1 is also involved in other cellular processes in the pituitary, such as cell division and survival, but the genomic targets involved in these actions are not known. The present ChIP-chip study identified a large number of hitherto unknown potential direct targets that might be involved in these actions, such as Tcf4, Lmo4, Pax6, Trp53 etc. ChIP-chip was done from pregnant female mouse (C57Bl/6J) pituitary (3 pools of 12 pituitary anterior lobes, corresponding to three biological replicates) with POU1F1 (PIT-1)
Project description:The anterior pituitary-specific transcription factor POU1F1 (also called PIT-1) was initially identified and cloned as a transactivator of PRL, GH and TSHß subunit genes. Different studies indicated that POU1F1 could also have other functions in these cells. The identification of new targets of this factor could be useful to obtain a better understanding of these functions. Gene expression microarray assays were used to detect genes that have their expression modified in somatolactotrope GH4C1 cells by the expression of a dominant negative form of POU1F1, POU1F1(R271W).
Project description:The anterior pituitary-specific transcription factor POU1F1 (also called PIT-1) was initially identified and cloned as a transactivator of PRL, GH and TSHß subunit genes. Different studies indicated that POU1F1 could also have other functions in these cells. The identification of new targets of this factor could be useful to obtain a better understanding of these functions. Gene expression microarray assays were used to detect genes that have their expression modified in somatolactotrope GH4C1 cells by the expression of a dominant negative form of POU1F1, POU1F1(R271W). Lentiviral vectors containing the transgene of interest under the control of the PGK promoter (pGK-POU1F1(R271W)-IRES-EGFP, or pGK-EGFP used as controls) were generated. After lentiviral transfer in GH4C1 cells were grown in regular medium for 4 days then cells were harvested and total RNA was purified.
Project description:The aim of the study is to evaluate Pit-1-induced genes in the MCF-7 cell line The Pit-1 transcription factor (also known as POU1F1) plays a critical role in cell differentiation during organogenesis of the anterior pituitary in mammals and is a transcriptional activator for pituitary gene transcription. Increased expression of Pit-1 has been reported in human tumorigenic breast cells. Here, we found that Pit-1 overexpression or knockdown in human breast cancer cell lines induced profound phenotypic changes in the expression of proteins involved in cell proliferation, apoptosis, and invasion. In immunodeficient mice, Pit-1 overexpression induced tumoral growth and promoted metastasis in lung. In patients with invasive ductal carcinoma of the breast and node-positive tumors elevated expression of Pit-1 was significantly and independently associated with the occurrence of distant metastasis. These findings suggest that Pit-1 could help to make a more accurate prognosis in patients with node positive breast cancer and may represent a new therapeutic target (Journal of Clinical Investigation 2010, 120:4289-4302) MCF-7 cells were transfected with the pcDNA3 (control, two samples as condition, named C1 and C2) or the pcDNA3-Pit-1 overexpression vector (two samples as condition, named 1+ and 2+) for 48 hours.
Project description:The aim of the study is to evaluate Pit-1-induced genes in the MCF-7 cell line The Pit-1 transcription factor (also known as POU1F1) plays a critical role in cell differentiation during organogenesis of the anterior pituitary in mammals and is a transcriptional activator for pituitary gene transcription. Increased expression of Pit-1 has been reported in human tumorigenic breast cells. Here, we found that Pit-1 overexpression or knockdown in human breast cancer cell lines induced profound phenotypic changes in the expression of proteins involved in cell proliferation, apoptosis, and invasion. In immunodeficient mice, Pit-1 overexpression induced tumoral growth and promoted metastasis in lung. In patients with invasive ductal carcinoma of the breast and node-positive tumors elevated expression of Pit-1 was significantly and independently associated with the occurrence of distant metastasis. These findings suggest that Pit-1 could help to make a more accurate prognosis in patients with node positive breast cancer and may represent a new therapeutic target (Journal of Clinical Investigation 2010, 120:4289-4302)
Project description:The high energetic cost of reproduction requires that female fertility be closely linked to metabolic status. However, the mechanisms by which the metabolic and reproductive systems communicate is still largely undefined. We have previously reported that signaling through the major metabolic cytokine leptin controls levels of the pituitary maturation determinant POU1F1 (also referred to as Pit1) that is required for optimal reproductive function. These studies further indicated that leptin increases POU1F1levels in females by promoting Pou1f1 mRNA translation, although the mechanism ofPou1f1 mRNA translation control is unknown. In this study, we report that the stem cell marker and mRNA translational control protein, Musashi, represses translation of the Pou1f1 mRNA. In FACS-sorted purified female somatotropes, Msi1 mRNA and Musashi protein levels are increased in the mouse model that lacks leptin signaling (Gh-CRE leprLepr-null), coincident with the observed attenuation of Pou1f1 mRNA translation. Single-cell RNA sequencing of pituitary cells from control female animals indicates that Msi1 and Pou1f1 mRNAs are co-expressed in Gh-expressing cells and immunocytochemistry analyses of these cells confirms that Musashi protein is present in the GH-containing somatotrope population. We demonstrate that Musashi interacts directly with the Pou1f1 mRNA 3’ UTR and exerts translational repression of a Pou1f1 mRNA translation reporter in vitro, and interacts with the Pou1f1 mRNA in vivo. These findings indicate a critical role for Musashi-mediated mRNA translational regulation in the coordination between metabolic status and the maturation of pituitary somatotropes that is required for optimized reproductive function .
Project description:POU1F1 regulates, in the pituitary, the development of the prolactin-, growth hormone- and thyrotropin ß-expressing lineages and the expression of these hormone in the mature pituitary through the direct regulation of their promoters. Besides these functions, POU1F1 is also involved in other cellular processes in the pituitary, such as cell division and survival, but the genomic targets involved in these actions are not known. The present ChIP-chip study identified a large number of hitherto unknown potential direct targets that might be involved in these actions, such as Tcf4, Lmo4, Pax6, Trp53 etc.
Project description:Sex differences in liver gene expression are dictated by sex-differences in circulating growth hormone (GH) profiles. Presently, the pituitary hormone dependence of mouse liver gene expression was investigated on a global scale to discover sex-specific early GH response genes that might contribute to sex-specific regulation of downstream GH targets and to ascertain whether intrinsic sex-differences characterize hepatic responses to plasma GH stimulation. RNA expression analysis using 41,000-feature microarrays revealed two distinct classes of sex-specific mouse liver genes: genes subject to positive regulation (class-I) and genes subject to negative regulation by pituitary hormones (class-II). Genes activated or repressed in hypophysectomized (Hypox) mouse liver within 30-90min of GH pulse treatment at a physiological dose were identified as direct targets of GH action (early response genes). Intrinsic sex-differences in the GH responsiveness of a subset of these early response genes were observed. Notably, 45 male-specific genes, including five encoding transcriptional regulators that may mediate downstream sex-specific transcriptional responses, were rapidly induced by GH (within 30min) in Hypox male but not Hypox female mouse liver. The early GH response genes were enriched in 29 male-specific targets of the transcription factor Mef2, whose activation in hepatic stellate cells is associated with liver fibrosis leading to hepatocellular carcinoma, a male-predominant disease. Thus, the rapid activation by GH pulses of certain sex-specific genes is modulated by intrinsic sex-specific factors, which may be associated with prior hormone exposure (epigenetic mechanisms) or genetic factors that are pituitary-independent, and could contribute to sex-differences in predisposition to liver cancer or other hepatic pathophysiologies.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Pituitary gland function is regulated by the activity of various transcription factors which control cell fate decisions leading to cellular differentiation and hormone production. FOXO1 is necessary for the proper timing of somatotrope differentiation and for somatotrope function, but the exact mechanism of action has yet to be elucidated. Recent data implicate FOXO1 in the regulation of genes important for somatotrope differentiation including Gh1, Neurod4, and Pou1f1. Previously, a mouse model with conditional deletion of Foxo1 from the developing pituitary gland displayed reduced Gh1 and Neurod4 transcripts as early as embryonic day 18.5. Additional data from adult animals with conditional deletion of both Foxo1 and Foxo3 from the pituitary gland have a similar reduction in Neurod4 and Gh1, as well as Pou1f1. To investigate the mechanism by which FOXO1 regulates pituitary gland gene expression and confirm in vivo findings, the somatotrope-like cell line, GH3, was treated with the FOXO1 inhibitor, AS1842856, for 24 hours at various concentrations. Neurod4 was the most severely affected genes with a dose-dependent reduction in transcript at inhibitor concentrations as low as 30 nM. Gh1 transcripts were significantly reduced at 300 nM. Pou1f1 expression was trending down at 3 microM inhibitor (p=0.066). Consistent with these findings, CRISPR/Cas9-mediated deletion of Foxo1 in GH3 cells significantly reduced expression of Gh1, Neurod4, but not Pou1f1. To elucidate the molecular mechanisms underlying the role of FOXO1 in somatotropes, ChIPseq was performed for FOXO1 in the GH3 cell line. This study identified novel FOXO1 binding sites associated with the Neurod4, Gh1, and Pou1f1 genes. The FOXO1 binding site in the Neurod4 gene exhibits enhancer activity in somatotrope-like cells, but not in gonadotrope-like or heterologous cells. These data strongly suggest FOXO1 directly contributes to the transcriptional control of genes important for somatotrope differentiation. These novel findings contribute to the much-needed understanding of pituitary cell fate decisions.