Project description:A growing number of studies have demonstrated that N6 methyladenine (m6A) acts as an important role in the pathogenesis of reproductive diseases, which makes it essential to profile the genome-wide m6A modifications in embryo damage. In this study, due to the microscopicity of early villous tissue, we performed high-throughput sequencing for villous tissues from three patients with embryo damage and three patients with painless abortion. Based on meRIP-seq data, we identified 18,568 m6A peaks from these two samples. These m6A peaks were mainly located in the coding region near the stop codon and were mainly characterized by AUGGAC and UGGACG motif. Compared with the normal group, the embryo damage group had 2,159 significantly upregulated m6A peaks and 281 downregulated m6A peaks. Genes with altered m6A peaks were mainly involved in Hippo and Wnt signaling pathways. Based on RNA-seq data, we found that differentially expressed genes were mainly involved in Th17 cell differentiation, TNF signaling pathway, and ECM-receptor interaction. Based on the conjoint analysis of meRIP-seq and RNA-seq data, we identified 36 genes with differentially methylated m6A peaks and synchronously differential expression. These genes were mainly involved in the Wnt signaling pathway, phosphatase activity regulation, protein phosphatase inhibitor activity, and transcription inhibitor activity. In general, our study revealed the transcriptome-wide m6A methylome in early embryonic development, which may provide novel insights into the pathogenesis and treatment of embryo damage.
Project description:N6-methyl-adenosine (m6A) is the most abundant modification on messenger RNAs and is linked to human diseases, but its functions in mammalian development are poorly understood. Here we reveal the evolutionary conservation and function of m6A by mapping the m6A methylome in mouse and human embryonic stem cells. Thousands of messenger and long noncoding RNAs show conserved m6A modification, including transcripts encoding core pluripotency transcription factors. m6A is enriched over 3M-bM-^@M-^Y untranslated regions at defined sequence motifs, and marks unstable transcripts, including transcripts turned over upon differentiation. Genetic inactivation or depletion of mouse and human Mettl3, one of the m6A methylases, led to m6A erasure on select target genes, prolonged Nanog expression upon differentiation, and impaired ESCM-bM-^@M-^Ys exit from self-renewal towards differentiation into several lineages in vitro and in vivo. Thus, m6A is a mark of transcriptome flexibility required for stem cells to differentiate to specific lineages. Examing m6A modification differences in two different cell types
Project description:Our study demonstrated that the expression of Igf2bp1 in activated microglia was significantly up-regulated, implying a role of Igf2bp1 in LPS-induced m6A modifications in microglia. To understand the roles of Igf2bp1 on LPS-induced m6A modification in microglia, we performed Igf2bp1 loss-of-function (LOF) approach. Microglia stimulated by LPS were transfected with either scrambled siRNA control or Igf2bp1 siRNA for 48 hours. To m6A modification profiles in control and Igf2bp1 LOF microglia were determined by MeRIP-seq analysis.
Project description:Here we determine the map of RNA methylation (m6A) in mouse embrionic stem cells, and Mettl3 knock out cells Examination of m6A modification sites on the transcriptome of mouse Embryonic stem cells and Embryonic Mettl3 knock out cells, using a m6A specific antibody.
Project description:In this study we performed MeRIP-Seq to study N6-methyl adenosine (m6A) and and N6,2′ -O-dimethyladenosine (m6Am) modification of mRNA. We investigated the effect of the microbiota on the transcriptome and epitranscriptomic modifications in murine liver and cecum. We compared m6A/m modification profiles in cecum of conventionally raised (CONV) and germ-free (GF) mice. We additionally included GF mice colonised with the flora of CONV mice for four weeks (ex-GF), for which show that they exhibit similar patterns of the most abundant genera of gut bacteria as CONV mice. We added mice treated with several antibiotics to deplete the gut flora (abx)and vancomycin treated mice in which the genera Akkermansia, Escherichia/Shigella and Lactobacillus were enriched. Furthermore, we included GF mice colonised with the commensal bacterium Akkermansia muciniphila (Am), Lactobacillus plantarum (Lp) and Escherichia coli Nissle (Ec) and analysed their m6A/m modification profiles. In addition, we analysed changes in m6A/m- modified liver RNA for CONV, GF, and Am, Lp and Ec mice.
Project description:N6-methyladenosine (m6A) RNA methylation is the most abundant modification on mRNAs and plays important roles in various biological processes. The formation of m6A is catalyzed by a methyltransferase complex including methyltransferase like 3 (METTL3) as a key factor. However, the in vivo functions of METTL3 and m6A modification in mammalian development remain unclear. Here we show that specific inactivation of Mettl3 in mouse nervous system causes severe developmental defects in the brain. Mettl3 conditional knockout mice manifest cerebellar hypoplasia caused by drastically enhanced apoptosis of new born cerebellar granule cells (CGCs) in the external granular layer (EGL). METTL3 depletion induced loss of m6A modification causes extended RNA half-lives and aberrant splicing events, consequently leading to dysregulation of transcriptome-wide gene expression and premature CGC death. Our findings reveal a critical role of METTL3-mediated m6A in regulating the development of mammalian cerebellum.
Project description:N6-methyladenosine (m6A) is a widespread reversible chemical modification of RNAs, implicated in many aspects of RNA metabolism. Little quantitative information exists as to either how many transcript copies of particular genes are m6A modified (âm6A levelsâ), or the relationship of m6A modification(s) to alternative RNA isoforms. To deconvolute the m6A epitranscriptome, we developed m6A level and isoform-characterization sequencing (m6A-LAIC-seq). We found that cells exhibit a broad range of non-stoichiometric m6A levels with cell type specificity. At the level of isoform characterization, we discovered widespread differences in use of tandem alternative polyadenylation (APA) sites by methylated and nonmethylated transcript isoforms of individual genes. Strikingly, there is a strong bias for methylated transcripts to be coupled with proximal APA sites, resulting in shortened 3â untranslated regions (3â-UTRs), while nonmethylated transcript isoforms tend to use distal APA sites. m6A-LAIC-seq yields a new perspective on transcriptome complexity and links APA usage to m6A modifications. m6A-LAIC-seq of H1-ESC and GM12878 cell lines, each cell line has two replicates
Project description:Faithful genome integrity maintenance plays an essential role in cell survival. Here, we identify the RNA demethylase ALKBH5 as a key regulator that protects cells from DNA damage and apoptosis during reactive oxygen species (ROS)-induced stress. We find that ROS significantly induces global mRNA N6-methyladenosine (m6A) levels by modulating ALKBH5 post-translational modifications (PTMs), leading to the rapid and efficient induction of thousands of genes involved in a variety of biological processes including DNA damage repair. Mechanistically, ROS promotes ALKBH5 SUMOylation through activating ERK/JNK signaling, leading to inhibition of ALKBH5 m6A demethylase activity by blocking substrate accessibility. Moreover, ERK/JNK/ALKBH5-PTMs/m6A axis is activated by ROS in hematopoietic stem/progenitor cells (HSPCs) in vivo in mice, suggesting a physiological role of this molecular pathway in the maintenance of genome stability in HSPCs. Together, our study uncovers a molecular mechanism involving ALKBH5 PTMs and increased mRNA m6A levels that protect genomic integrity of cells in response to ROS.