Project description:The maternal-to-zygotic transition (MZT) is a conserved and fundamental process during which the embryo undergoes dramatic reprogramming to convert maternal environment to embryonic-driven programing. However, how the maternally supplied transcripts are dynamically regulated during MZT remains largely unknown. Herein, through genome-wide profiling of RNA 5-methylcytosine (m5C) in zebrafish early embryos, we show that m5C methylated maternal mRNAs display higher stability during MZT. We identify that the Y box-binding protein 1 (Ybx1) prefers to recognizing m5C-modified mRNAs through p-p interaction with a key residue Trp45 in its cold shock domain (CSD), which plays essential roles in maternal mRNA stability and early embryogenesis of zebrafish. Cooperated with an mRNA stabilizer Pabpc1a, Ybx1 promotes the stability of its target mRNAs in an m5C-dependent manner. Our study demonstrates a novel mechanism of RNA m5C methylation-regulated maternal mRNA stability during zebrafish MZT, highlighting the critical role of m5C mRNA methylation in early development.
Project description:Total RNA was isolated from zebrafish embryos harvested at different stages using TRIzol® Reagent (Ambion). mRNA was extracted with using Dynabeads® mRNA Purification Kit (Ambion) and subjected to TURBO™ DNase (Invitrogen) treatment at 37°C for 30 min and ethanol precipitation. Thus purified mRNA was used for RNA-BisSeq library construction. Around 200 ng mRNA premixed with the in vitro transcribed Dhfr mRNA at a ratio of 300:1 (Dhfr mRNA serves as methylation conversion control) was fragmented to ~100-nt fragments for 1 min at 90°C in 10× RNA Fragmentation Reagent (Ambion), then stopped by 10× RNA stop solution (Ambion), and precipitated with 100% ethanol. The RNA pellet was resuspended in 100 µl bisulfite solution (pH 5.1), which is a 100:1 mixture of 40% sodium bisulfite (Sigma) and 600 µM hydroquinone (Sigma) and subjected to heat incubation at 75°C for 4.5 h. The reaction mixture was desalted by passing through Nanosep with 3K Omega 500/pk columns (PALL Corporation) with centrifugation. After washed with nuclease-free water and centrifuged for five times, the RNA was finally disolved in 75 μl nuclease-free water and then desulfonated by incubation with an equal volume of 1 M Tris-HCl (pH 9.0) at 75 °C for 1 h. After ethanol precipitation, the RNA was resuspended in 11 µl of RNase-free water and subjected to library construction. Reverse transcription was carried out with superscript II Reverse Transcriptase (Invitrogen) and ACT random hexamers. The following procedures were performed with the KAPA Stranded mRNA-Seq Kit (KAPA) according to the manufacturer’s instructions.Libraries were sequenced using HiSeq2500 (Illumina) in paired-read mode, creating reads with a length of 125 bp.
Project description:The maternal-to-zygotic transition (MZT) is a conserved and fundamental process during which the embryo undergoes dramatic reprogramming to convert maternal environment to embryonic-driven programing. However, how the maternally supplied transcripts are dynamically regulated during MZT remains largely unknown. Herein, through genome-wide profiling of RNA 5-methylcytosine (m5C) in zebrafish early embryos, we show that m5C methylated maternal mRNAs display higher stability during MZT. We identify that the Y box-binding protein 1 (Ybx1) prefers to recognizing m5C-modified mRNAs through p-p interaction with a key residue Trp45 in its cold shock domain (CSD), which plays essential roles in maternal mRNA stability and early embryogenesis of zebrafish. Cooperated with an mRNA stabilizer Pabpc1a, Ybx1 promotes the stability of its target mRNAs in an m5C-dependent manner. Our study demonstrates a novel mechanism of RNA m5C methylation-regulated maternal mRNA stability during zebrafish MZT, highlighting the critical role of m5C mRNA methylation in early development.
Project description:We analyzed transcriptome profiles at 8 hours post fertilization of zebrafish embryo which were injected with/without nfr2a mRNA into a 1-cell stage embryo by using the Zebrafish gene expression microarray (MZH_Zebrafish_16k_v1.0).
Project description:RNA m5C methylation profile of MCF10A and MDA486 by using MeRIP-Seq protocol Immunoprecipitation of Methylated mRNA at Cytosine (m5C) residues: Affinity purified of anti-methyl cytosine (m5C) polyclonal antibody 7ug (Zymo Research, Catalog#A3001-50) was conjugated with protein-A magnetic beads for 2 h at 4°C in end to end rotator. After that, conjugated beads were extensively washed with RNA immunoprecipitation (RIP) wash buffer to remove unbound antibody. Fragmented 25 ug polyA RNA (mRNA) was incubated with m5C conjugated beads for overnight at 4°C in in the rotating platform in RIP buffer. RIP was done using Megna RNA Immunoprecipitation kit (Millipore, Catalog#17-700). m5C mRNA-immune bead complex was treated with proteinase K buffer to release m5C mRNA from the conjugated antibody. To isolate m5C, mRNA was treated with phenol:chloroform:isoamyl and mixed with 400 ul of chloroform, which was centrifuged at 14000 rpm for 10 minutes to separate aqueous phase. The aqueous phase was ethanol precipitated at -80°C for overnight, to get m5C mRNA. This precipitated m5C mRNA pellet was washed twice with 70% ethanol and air dried. Finally, m5C mRNA pellet was dissolved in nuclease free Water. The m5C mRNA integrity and conentration was quantified by bioanalyzer (Agilent) and Qubit 2.0 flurometer (Invitrogen). The fragmented mRNA was used by following TruSeq RNA Sample Preparation Guide to develop RNA-Seq library for sequencing.
Project description:The epigenetic modifications play important regulatory roles in tissue development, maintenance of physiological functions and pathological process. RNA methylations, including newly identified m1A, m5C, m6A and m7G, are important epigenetic modifications. However, how these modifications are distributed in the transcriptome of vertebrate brains and whether their abundance is altered under pathological conditions are still poorly understood. In this study, we chose the model animal of zebrafish to conduct a systematic study to investigate the mRNA methylation atlas in the brain. By performing unbiased analyses of the m1A, m5C, m6A and m7G methylation of mRNA, we found that within the whole brain transcriptome, with the increase of the gene expression levels, the overall level of each of these four modifications on the related genes was also progressively increased. Further bioinformatics analysis indicated that the zebrafish brain has an abundance of m1A modifications. In the hypoxia-treated zebrafish brains, the proportion of m1A is decreased, affecting the RNA splicing and zebrafish endogenous retroviruses. Our study presents the first comprehensive atlas of m1A, m5C, m6A and m7G in the epitranscriptome of the zebrafish brain and reveals the distribution of these modifications in mRNA under hypoxic conditions. These data provide an invaluable resource for further research on the involvement of m1A, m5C, m6A and m7G in the regulation of miRNA and repeat elements in vertebrates, and provide new thoughts to study the brain hypoxic injury on the aspect of epitranscriptome.