Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:DNA methylation marks are thought to be set up during early development and to remain static thereafter in healthy tissues. Here, we characterize the liver DNA methylation patterns of mice before birth, during early postnatal development (from birth until weaning) and in adulthood. Our analyses show extensive epigenetic reprogramming in the liver occurring during postnatal development. 118,877 of 261,317 CpGs analyzed throughout the genome significantly changed their methylation level by more than 5% from birth to nine weeks of age, with some changing by up to 86%. Interestingly, changes in DNA methylation occur primarily in intergenic enhancer regions while gene promoters seem little affected. Analysis of 166 CpGs at multiple time points by locus-specific bisulfite sequencing reveals that this reprogramming primarily occurs between postnatal day 1 and day 20. This time period coincides with two major cellular changes in the liver: the differentiation of hepatocytes and extensive cell division. While cell multiplication leaves a distinct footprint on the DNA methylation patterns, we show that the extensive epigenetic reprogramming likely results from differentiation of hepatoblasts into hepatocytes. Overall, our data suggest that epigenetic remodeling is an important aspect of normal liver maturation and involves a large number of gene enhancers.
Project description:DNA methylation marks are thought to be set up during early development and to remain static thereafter in healthy tissues. Here, we characterize the liver DNA methylation patterns of mice before birth, during early postnatal development (from birth until weaning) and in adulthood. Our analyses show extensive epigenetic reprogramming in the liver occurring during postnatal development. 118,877 of 261,317 CpGs analyzed throughout the genome significantly changed their methylation level by more than 5% from birth to nine weeks of age, with some changing by up to 86%. Interestingly, changes in DNA methylation occur primarily in intergenic enhancer regions while gene promoters seem little affected. Analysis of 166 CpGs at multiple time points by locus-specific bisulfite sequencing reveals that this reprogramming primarily occurs between postnatal day 1 and day 20. This time period coincides with two major cellular changes in the liver: the differentiation of hepatocytes and extensive cell division. While cell multiplication leaves a distinct footprint on the DNA methylation patterns, we show that the extensive epigenetic reprogramming likely results from differentiation of hepatoblasts into hepatocytes. Overall, our data suggest that epigenetic remodeling is an important aspect of normal liver maturation and involves a large number of gene enhancers.
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:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:PGCs undergo two distinct stages of demethylation before reaching a hypomethylated ground state at E13.5. Stage 1 occurs between E7.25- E9.5 in which PGCs experience a global loss of cytosine methylation. However, discreet loci escape this global loss of methylation and between E10.5-E13.5, stage 2 of demethylation takes place. In this stage these loci are targeted by Tet1 and Tet2 leading to the loss of the remaining methylation and resulting in the epigenetic ground state. Our data shows that Dnmt1 is responsible for maintaining the methylation of loci that escape stage 1 demethylation, and that it functions in a UHRF1 independent manner. Our data further demonstrates that when these loci lose methylation prior to stage 2 it results in early activation of the meiotic program, which leads to precocious differentiation of the germ line resulting in a decreased pool of PGCs in the embryo and subsequent infertility in adult mice.