Project description:∼40,000 HNF6 binding sites were identified in mouse liver chromatin, including several thousand sites showing significant differences in level of HNF6 binding between male and female mouse liver. These sex-biased HNF6 binding sites showed strong enrichment for sex-biased DNase hypersensitive sites and for proximity to genes showing local sex-biased chromatin marks and a corresponding sex-biased expression. ~90% of genome-wide CUX2 binding sites identified previously in female mouse liver (Conforto TL, Zhang Y, Sherman J, Waxman DJ., Mol Cell Biol. 2012;32(22):4611-4627) were also bound by HNF6, giving evidence for genome-wide competition between HNF6 and CUX2 for chromatin binding in female mouse liver. These HNF6/CUX2 common binding sites were enriched for genomic regions more accessible in male than in female mouse liver chromatin, and showed strongest enrichment for male-biased genes, suggesting HNF6 displacement by CUX2 as a mechanism to explain the observed CUX2 repression of male-biased genes in female liver. However, HNF6 binding was sex-independent at a majority of its binding sites, and peak regions of HNF6 binding were frequently associated with co-binding by multiple other liver transcription factors, consistent with HNF6 playing a global regulatory role in both male and female liver.
Project description:∼40,000 HNF6 binding sites were identified in mouse liver chromatin, including several thousand sites showing significant differences in level of HNF6 binding between male and female mouse liver. These sex-biased HNF6 binding sites showed strong enrichment for sex-biased DNase hypersensitive sites and for proximity to genes showing local sex-biased chromatin marks and a corresponding sex-biased expression. ~90% of genome-wide CUX2 binding sites identified previously in female mouse liver (Conforto TL, Zhang Y, Sherman J, Waxman DJ., Mol Cell Biol. 2012;32(22):4611-4627) were also bound by HNF6, giving evidence for genome-wide competition between HNF6 and CUX2 for chromatin binding in female mouse liver. These HNF6/CUX2 common binding sites were enriched for genomic regions more accessible in male than in female mouse liver chromatin, and showed strongest enrichment for male-biased genes, suggesting HNF6 displacement by CUX2 as a mechanism to explain the observed CUX2 repression of male-biased genes in female liver. However, HNF6 binding was sex-independent at a majority of its binding sites, and peak regions of HNF6 binding were frequently associated with co-binding by multiple other liver transcription factors, consistent with HNF6 playing a global regulatory role in both male and female liver. Livers were excised from individual male and female mice, cross-linked and sonicated, then used to identify HNF6 binding sites by ChIP-Seq using antibody specific to HNF6 (sc-13050; Santa Cruz Biotechnology, Inc).
Project description:We identified genes expressed in mouse liver that are regulated by Cux2, a highly female-specific liver transcription factor whose expression is regulated by sex-dependent plasma GH patterns. Using siRNA to knockdown Cux2 expression in female liver, we show that female specific genes are predominantly repressed by Cux2 knockdown. In contrast, similar numbers of male-biased genes are repressed as are induced by Cux2 knockdown. A scrambled, non-specific siRNA was used as a control. (Published in: TL Conforto et al 2012, Mol Cell Biol. 2012, 32:4611-4627. PubMed PMID: 22966202; PMCID: PMC3486175)
Project description:We identified genes expressed in mouse liver that are regulated by Cux2, a highly female-specific liver transcription factor whose expression is regulated by sex-dependent plasma GH patterns. Using adenovirus to overexpress Cux2 (Adeno-Cux2) in male liver, we show that Cux2 represses ~35% of male-biased genes and induces/de-represses ~35% of female-biased genes. Adeno-CMV was used as a control for adenoviral infection. (Published in: TL Conforto et al 2012, Mol Cell Biol. 2012, 32:4611-4627. PubMed PMID: 22966202; PMCID: PMC3486175)
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:Microarray analysis of male and female CD-1 mouse liver was carried out at 3, 4, and 8 wk of age to elucidate developmental changes in gene expression from the pre-pubertal period to young adulthood. A large number of sex-biased and sex-independent genes showed significant changes during this developmental period. Notably, sex-independent genes involved in cell cycle, chromosome condensation, and DNA replication were down regulated from 3 wk to 8 wk, while genes associated with metal ion binding, ion transport and kinase activity were up regulated. A majority of genes showing sex differential expression in adult liver did not display sex differences prior to puberty, at which time extensive changes in sex-specific gene expression were seen, primarily in males. Thus, in male liver, 76% of male-specific genes were up regulated and 47% of female-specific genes were down regulated from 3 to 8 wk of age, whereas in female liver 67% of sex-specific genes showed no significant change in expression. In both sexes, genes up regulated from 3 to 8 wk were significantly enriched (p < E-76) in the set of genes positively regulated by the liver transcription factor HNF4α, as determined in a liver-specific HNF4α knockout mouse model, while genes down regulated during this developmental period showed significant enrichment (p < E-65) for negative regulation by HNF4α. Significant enrichment of the developmentally regulated genes in genes subject to positive and negative regulation by pituitary hormone was also observed. Nine sex-specific transcription factors showed pubertal changes in expression and may contribute to the developmental changes that onset after 3-4 wk. Overall, the observed changes in gene expression during postnatal liver development reflect the deceleration of liver growth and the induction of specialized liver functions, with widespread changes in sex-specific gene expression primarily occurring in male liver.
Project description:We identified genes expressed in mouse liver that are regulated by Cux2, a highly female-specific liver transcription factor whose expression is regulated by sex-dependent plasma GH patterns. Using adenovirus to overexpress Cux2 (Adeno-Cux2) in male liver, we show that Cux2 represses ~35% of male-biased genes and induces/de-represses ~35% of female-biased genes. Adeno-CMV was used as a control for adenoviral infection. (Published in Molec Cell Biology, TL Conforto et al, 2012) Liver RNA isolated from the following eight groups of mice was used in the present study: (1) 8 wk old untreated male (M) mice (n = 10; 5 per each pool); (2) 8 wk old untreated female mice (F) mice (n = 11; 5 or 6 per each pool); (3) 8 wk old male mice treated with Adeno-Cux2 and euthanized 5 days later (n = 12; 6 per each pool); (4) 8 wk old female mice treated with Adeno-Cux2 and euthanized 5 days later (n = 8; 4 per each pool); (5) 8 wk old male mice treated with Adeno-CMV and euthanized 5 days later (n = 13; 6 or 7 per each pool); (6) 8 wk old female mice treated with Adeno-CMV and euthanized 5 days later (n = 7; 3 or 4 per each pool); (7) 8 wk old male mice treated with Adeno-Cux2 and euthanized 3 days later (n=11; 5 or 6 per each pool); (8) 8 wk old male mice treated with Adeno-CMV and euthanized 3 days later (n=11; 5 or 6 per pool). These RNA pools were used in four separate sets of competitive hybridization experiments: 1) 8 wk untreated M vs. 8 wk untreated F; 2) 8 wk M + Ad-Cux2 (5 day) vs. 8 wk M + Ad-CMV (5 day); 3) 8 wk F + Ad-Cux2 (5 day) vs. 8 wk F + Ad-CMV (5 day); 4) 8 wk M + Ad-Cux2 (3 day) vs. 8 wk M + Ad-CMV (3 day). Fluorescent labeling of RNA and hybridization of the Alexa 555-labeled (green) and Alexa 647-labeled (red) RNA samples to Agilent Mouse Gene Expression 4x44k v1 microarrays (Agilent Technology, Palo Alto, CA; catalog # G4122F-014868) were carried out, with dye swapping for each of the three hybridization experiments to eliminate dye bias. Two microarrays, one for each mixed cDNA sample, were hybridized for each of the four fluorescent reverse pairs, giving a total of 8 microarrays.
Project description:Growth hormone (GH)-regulated transcription factors, notably STAT5 and BCL6, play a major role in regulating genes showing sex differences in expression in mouse liver, primarily through their effects in male liver, where male-biased genes are up regulated and many female-biased genes are actively repressed. Here we investigate whether complementary mechanisms, involving up regulation of female-biased genes and down regulation of male-biased genes occur in female liver. To address this question, we identified genes regulated by Cux2, a highly female-specific transcription factor that is repressed in male liver and is induced by the female plasma GH pattern in female liver. ChIP-seq analysis identified Cux2 binding sites in female liver only, where they are enriched at sites of male-biased DNase hypersensitivity and at genomic regions showing male-enriched STAT5 binding. Cux2 binding sites were enriched at genes repressed by adenoviral-Cux2, but not at genes induced by adenoviral-Cux2 (see GSE35897), indicating a direct binding mechanism in Cux2 repression but not in Cux2-dependent gene induction. (Published in: TL Conforto et al 2012, Mol Cell Biol. 2012, 32:4611-4627. PubMed PMID: 22966202; PMCID: PMC3486175) Mouse livers were excised from individual male and female. Sonicated, cross-linked liver nuclear chromatin was then used to identify Cux2 binding sites by ChIP-Seq using antibody specific to Cux2, amino acids 356 to 415