Project description:Neurodevelopment is a tightly coordinated process, in which genome is exposed to spectra of endogenous agents at different stages of differentiation. Increasing body of evidence suggests that DNA damage is an important feature of developing brain, tightly linked to gene expression programs and neuronal activity. Some of the most frequent DNA damage includes changes to DNA bases, recognized by DNA glycosylases and repaired through base excision repair (BER). The only mammalian DNA glycosylase able to remove frequent alkylated DNA based is alkyladenine DNA glycosylase (Aag, aka Mpg). Recently we showed that, besides participation in DNA repair, AAG affects expression of neurodevelopmental genes in human cells. Aag was further proposed to act as reader of epigenetic marks, including 5-hydroxymethylcytosine (5hmC), in the mouse brain. Despite the evidence of potential Aag involvement in the key brain processes, the impact of Aag loss on developing brain remains unknown. Here, by using Aag knockout (Aag-/-) mice, we show that Aag absence leads to reduced DNA damage levels, evident in lowered number of γH2AX foci in P5 hippocampi. This is accompanied by changes in 5hmC signal intensity in different hippocampal regions. Analysis of gene expression in hippocampus and prefrontal cortex, at multiple developmental stages, indicates that lack of Aag results in altered gene expression, primarily of genes involved in regulation of response to stress. One of the most prominent genes deregulated in Aag-dependent manner, at all tested developmental stages, is aldehyde dehydrogenase 2 (Aldh2). In line with the changes in hippocampal DNA damage levels and the gene expression, adult Aag-/- mice exhibit altered behavior, evident in decreased anxiety in the Elevated Zero Maze and increased alternations in the Elevated T Maze tests. Taken together these results suggests that Aag has functions in modulation of genome dynamics during brain development, important for animal behavior.
Project description:Base excision repair (BER) initiated by alkyladenine DNA glycosylase (AAG; aka MPG) is essential for removal of aberrantly methylated DNA bases. Genome instability and accumulation of aberrant bases accompany multiple diseases including cancer and neurological disorders. While BER is well studied on naked DNA, it is currently unclear how BER efficiently operates on chromatin. Here we show that AAG binds to chromatin and forms a complex with active RNA polymerase (pol) II. This occurs through direct binding to Elongator and results in co-regulation of gene expression. Interestingly, endogenous aberrantly methylated bases accumulate at 3’end of co-regulated genes, in regions enriched for Elongator, active RNA pol II, and BER enzymes AAG and APE1. Active transcription and functional Elongator are further vital to ensure efficient BER by promoting AAG and APE1 chromatin occupancy. Our findings indicate that AAG needs to associate with transcription elongation to maintain genome stability, concurrently coordinating repair with gene expression.
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:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
