Systematic Study Of RNA Editing And MiRNA Editing In Mammalian Spermatogenesis

Infertility is gaining increasing attention which affects about 15% couples all over the world.About half of them suffer from male reproductive abnormalities,and spermatogenesis is an important factor leading to male infertility.Our work aims to provide insights into the possible causes and treatments of spermatogenesis disorders by understanding the process of spermatogenesis and analyzing the molecular mechanisms of transcription and post-transcriptional regulation that affect gene expression during spermatogenesis.Spermatogenesis is a complex and dynamic process that requires a series of genes to coordinate and accurately express at each stage,a disorder in gene expression at any stage may affect spermatogenesis.RNA editing and miRNA editing as important posttranscriptional regulation of genes,affecting and regulating gene expression in a more flexible and efficient manner through the substitution,insertion and deletion of bases at the RNA level.If they exist,how they distribute in different germ cells,which reproductive genes are involved,and whether they affect the expression of these genes,these problems have not been resolved.In this study,we took advantage of big data and collected the published RNA-seq datasets.We analyzed both RNA editing and noncoding RNA editing of multiple stages of germ cells,and explained the editing situation of some genes and miRNAs that are known to play an important role in spermatogenesis.The specific process and results are as follows:1.Construction of RNA-seq data platform during spermatogenesisWe collected RNA-seq and non-coding RNA-seq samples of mouse spermatogenesis from the GEO and SRA databases as experimental data sets for RNA editing and miRNA editing calling.We grouped the datasets based on cell type and integrated samples from the same cell type into one.The results show that the integration strategy increases the sequencing depth to a certain extent,at the same time,consistent editing sites can be obtained from different samples,which can improve the accuracy compared to detecting RNA editing sites in each sample separately.2.RNA editing during spermatogenesisWe identified 7,530 editing sites in 2012 genes of 7 germ cells during mouse spermatogenesis.These editing sites exhibit a special distribution on some chromosomes,with the highest distribution density on chromosome 17,and the editing sites on the Y chromosome only distribute at both ends of the Y chromosome.Editing sites mainly exist in introns,intergenic and coding sequences(CDSs),and nearly half of the editing sites in CDSs will result in amino acid changes.Non-synonymous editings have been identified in genes that play an important role in spermatogenesis,such as Ddx3 x,Hjurp,Adad1,Tssk6,etc.,reflecting the flexible regulation of key genes' expression by RNA editing during spermatogenesis.3.miRNA editing during spermatogenesisWe identified 630 and 261 editing sites from mouse and pig,respectively.There are many consistent miRNA editing phenomena between the two species,such as the number of editing sites in different cells,the type of editing,and the distribution density of A-to-I editing in the seed region and non-seed region.Nearly half of miRNA editing events occur in the seed region,both in mouse and pig,which means that nearly half of the editing events may affect miRNA function.Finally,we found that miR-34 c,which is frequently edited during spermatogenesis,regulates target genes by altering its structure and displays dysfunction after being edited.In summary,we depict an overall overview of miRNA editing during mouse and pig spermatogenesis.