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Summary Reliably generating rice varieties with low glycaemic index (GI) is an important nutritional intervention given the high rates of Type II diabetes incidences in Asia where rice is staple diet. We integrated a genome‐wide association study (GWAS) with a transcriptome‐wide association study (TWAS) to determine the genetic basis of the GI in rice. GWAS utilized 305 re‐sequenced diverse indica panel comprising ~2.4 million single nucleotide polymorphisms (SNPs) enriched in genic regions. A novel association signal was detected at a synonymous SNP in exon 2 of LOC_Os05g03600 for intermediate‐to‐high GI phenotypic variation. Another major hotspot region was predicted for contributing intermediate‐to‐high GI variation, involves 26 genes on chromosome 6 (GI6.1). These set of genes included GBSSI, two hydrolase genes, genes involved in signalling and chromatin modification. The TWAS and methylome sequencing data revealed cis‐acting functionally relevant genetic variants with differential methylation patterns in the hot spot GI6.1 region, narrowing the target to 13 genes. Conversely, the promoter region of GBSSI and its alternative splicing allele (G allele of Wxa) explained the intermediate‐to‐high GI variation. A SNP (C˃T) at exon‐10 was also highlighted in the preceding analyses to influence final viscosity (FV), which is independent of amylose content/GI. The low GI line with GC haplotype confirmed soft texture, while other two low GI lines with GT haplotype were characterized as hard and cohesive. The low GI lines were further confirmed through clinical in vivo studies. Gene regulatory network analysis highlighted the role of the non‐starch polysaccharide pathway in lowering GI.

Aims/Introduction The incidence of type 2 diabetes mellitus is increasing worldwide, and it might partly cause metabolic disorder and type 2 diabetes mellitus susceptibility in patients’ offspring through epigenetic modification. However, the underlying mechanisms remain largely unclear. Recent studies have shown a potential link between deoxyribonucleic acid methylation in paternal sperm and susceptibility to type 2 diabetes mellitus in offspring, so this article focuses on whether the whole‐genome methylation profiles of spermatozoa in type 2 diabetes mellitus patients have changed. Materials and Methods We investigated the genome‐wide deoxyribonucleic acid methylation profiles in spermatozoa by comparing eight individuals with type 2 diabetes mellitus and nine non‐diabetic controls using whole‐genome bisulfite sequencing method. Results First, we found that the proportion of methylated cytosine in the whole genome of the type 2 diabetes mellitus group was slightly lower than that of the control group. Interestingly, the proportion of methylated cytosines in the CG context decreased, and the proportion of methylated cytosines in the CHG context (H = A, T or C) increased in the type 2 diabetes mellitus group, but the proportion of methylated cytosines in the CHH context (H = A, T or C) barely changed. The methylated cytosines in the CG context were mainly distributed at the high methylated level, whereas methylated cytosines in the CHG context and methylated cytosines in the CHH context were mainly distributed at the low and middle methylated level in both groups. Second, functional enrichment analysis showed that differentially methylated genes played a significant role in nervous system development and cell metabolism. Finally, we identified 10 top type 2 diabetes mellitus‐related differentially methylated genes, including IRS1, PRKCE, FTO, PPARGC1A, KCNQ1, ATP10A, GHR, CREB1, PRKAR1A and HNF1B. Conclusions Our study provides the first evidence for deoxyribonucleic acid methylation reprogramming in spermatozoa of type 2 diabetes mellitus patients, and provides a new basis for explaining the complex mechanism of type 2 diabetes mellitus susceptibility in offspring. Type 2 diabetes mellitus has an increasing global prevalence, and partly contributes to the susceptibility to metabolic dysregulation and type 2 diabetes mellitus in offspring through epigenetic modifications. However, the underlying mechanism remains largely obscure. Recent work has shown a potential link between paternal sperm deoxyribonucleic acid methylation and susceptibility to type 2 diabetes mellitus in offspring.

Gene methylation in cells is an important factor in tumorigenesis, and radiotherapy can change DNA methylation in cells. In this study, complete genome methylation sequencing (BS-Seq) technology was used to analyze the genome-wide methylation of patients with cervical cancer before and after radiotherapy. Three pairs of cervical squamous cell carcinoma samples were collected from patients before and after radiotherapy in July 2020. Genome-wide DNA methylation profiles were generated using WGBS. Bioinformatics analysis was conducted to identify differential methylation regions (DMRs) and their associated genes and pathways. The study focused on the methylation changes of LHX2, LHX5, and LHX9 genes, assessing their expression levels using qRT-PCR and correlating these changes with cervical cancer stages. MCG was the main way of genomic DNA methylation in the three patients. The DNA methylation level and methylation density on each chromosome varied greatly. As revealed by comparison of methylation before and after radiation in the three patients, 1287, 1261 and 789 differential methylation genes were identified, respectively. 3) Combined with clinical treatment, methylation level difference and correlation enrichment analysis, it was found that LHX2, LHX5 and LHX9 were closely related to the occurrence and development of cervical cancer. After 5-Aza-DC and radiotherapy, the methylation of the CpG islands in LHX2, LHX5 and LHX9 genes in these patients was decreased (p < 0.01), and the mRNA and protein expression levels were relatively increased (p < 0.01). In our present work, genome-wide DNA methylation maps of cervical cancer tissues before and after radiotherapy were successfully constructed. We found that LHX5 and LHX9 genes are closely related to cervical cancer. LHX5 and LHX9 have a negative effect on cervical cancer. The migration ability of LHX9 silenced cells was significantly enhanced after irradiation.

Background There is increasing evidence for inter-individual methylation differences at CpG dinucleotides in the human genome, but the regional extent and function of these differences have not yet been studied in detail. For identifying regions of common methylation differences, we used whole genome bisulfite sequencing data of monocytes from five donors and a novel bioinformatic strategy. Results We identified 157 differentially methylated regions (DMRs) with four or more CpGs, almost none of which has been described before. The DMRs fall into different chromatin states, where methylation is inversely correlated with active, but not repressive histone marks. However, methylation is not correlated with the expression of associated genes. High-resolution single nucleotide polymorphism (SNP) genotyping of the five donors revealed evidence for a role of cis -acting genetic variation in establishing methylation patterns. To validate this finding in a larger cohort, we performed genome-wide association studies (GWAS) using SNP genotypes and 450k array methylation data from blood samples of 1128 individuals. Only 30/157 (19%) DMRs include at least one 450k CpG, which shows that these arrays miss a large proportion of DNA methylation variation. In most cases, the GWAS peak overlapped the CpG position, and these regions are enriched for CREB group, NF-1, Sp100 and CTCF binding motifs. In two cases, there was tentative evidence for a trans -effect by KRAB zinc finger proteins. Conclusions Allele-specific DNA methylation occurs in discrete chromosomal regions and is driven by genetic variation in cis and trans , but in general has little effect on gene expression.

In the analysis of next-generation sequencing technology, massive discrete data are generated from short read counts with varying biological coverage. Conducting conditional hypothesis testing such as Fisher's Exact Test at every genomic region of interest thus leads to a heterogeneous multiple discrete testing problem. However, most existing multiple testing procedures for controlling the false discovery rate (FDR) assume that test statistics are continuous and become conservative for discrete tests. To overcome the conservativeness, in this article, we propose a novel multiple testing procedure for better FDR control on heterogeneous discrete tests. Our procedure makes decisions based on the marginal critical function (MCF) of randomized tests, which enables achieving a powerful and non-randomized multiple testing procedure. We provide upper bounds of the positive FDR (pFDR) and the positive false non-discovery rate (pFNR) corresponding to our procedure. We also prove that the set of detections made by our method contains every detection made by a naive application of the widely-used q-value method. We further demonstrate the improvement of our method over other existing multiple testing procedures by simulations and a real example of differentially methylated region (DMR) detection using whole-genome bisulfite sequencing (WGBS) data.

DNA methylation contributes to gene and transcriptional regulation in eukaryotes, and therefore has been hypothesized to facilitate the evolution of plastic traits such as sociality in insects. However, DNA methylation is sparsely studied in insects. Therefore, we documented patterns of DNA methylation across a wide diversity of insects. We predicted that underlying enzymatic machinery is concordant with patterns of DNA methylation. Finally, given the suggestion that DNA methylation facilitated social evolution in Hymenoptera, we tested the hypothesis that the DNA methylation system will be associated with presence/absence of sociality among other insect orders. We found DNA methylation to be widespread, detected in all orders examined except Diptera (flies). Whole genome bisulfite sequencing showed that orders differed in levels of DNA methylation. Hymenopteran (ants, bees, wasps and sawflies) had some of the lowest levels, including several potential losses. Blattodea (cockroaches and termites) show all possible patterns, including a potential loss of DNA methylation in a eusocial species whereas solitary species had the highest levels. Species with DNA methylation do not always possess the typical enzymatic machinery. We identified a gene duplication event in the maintenance DNA methyltransferase 1 (DNMT1) that is shared by some Hymenoptera, and paralogs have experienced divergent, nonneutral evolution. This diversity and nonneutral evolution of underlying machinery suggests alternative DNA methylation pathways may exist. Phylogenetically corrected comparisons revealed no evidence that supports evolutionary association between sociality and DNA methylation. Future functional studies will be required to advance our understanding of DNA methylation in insects.

Background Cancers have long been recognized to be not only genetically but also epigenetically distinct from their tissues of origin. Although genetic alterations underlying oncogene upregulation have been well studied, to what extent epigenetic mechanisms, such as DNA methylation, can also induce oncogene expression remains unknown. Results Here, through pan-cancer analysis of 4174 genome-wide profiles, including whole-genome bisulfite sequencing data from 30 normal tissues and 35 solid tumors, we discover a strong correlation between gene-body hypermethylation of DNA methylation canyons, defined as broad under-methylated regions, and overexpression of approximately 43% of homeobox genes, many of which are also oncogenes. To gain insights into the cause-and-effect relationship, we use a newly developed dCas9-SunTag-DNMT3A system to methylate genomic sites of interest. The locus-specific hypermethylation of gene-body canyon, but not promoter, of homeobox oncogene DLX1, can directly increase its gene expression. Conclusions Our pan-cancer analysis followed by functional validation reveals DNA hypermethylation as a novel epigenetic mechanism for homeobox oncogene upregulation.

The juvenile in vitro embryo transfer technology holds the potential to accelerate livestock breeding. However, its application is limited due to the weak in vitro development of oocytes and embryos from prepubertal lambs. To dissect the regulatory networks of gene expression of sheep embryos and identify the defects in gene expression in prepubertal lamb embryos during the oocyte-to-embryo transition, full-length RNA sequencing and whole-genome bisulfite sequencing based on trace cells were conducted on in vitro-derived embryos generated from adult sheep and prepubertal lamb oocytes. We found that the maternal transcript degradation occurred selectively in adult sheep embryos in multiple waves and was most completed until the morula stage. Major embryonic genome activation was found to occur at the morula stage. By comparing with the patterns of adult embryos, we observed incomplete maternal transcript degradation and abnormal embryonic genome activation in lamb embryos and analyzed their potential molecular mechanisms. Furthermore, we explored dynamic DNA methylation concerning the paternal and maternal genomes during the preimplantation development of sheep embryos, revealing the negative regulatory role of promoter DNA methylation on embryonic genome activation process. Lamb embryos generally displayed higher DNA methylation levels than adults, potentially repressing the embryonic genome activation gene expression, especially the genes associated with ribosomal and mitochondrial organization. We also found abnormalities in the methylation status of imprinted genes in lamb embryos. Our findings advance the understanding of sheep in vitro embryo development and offer insights for improving the juvenile in vitro embryo transfer technology in livestock. Summary Sentence Incomplete maternal transcript degradation, abnormal embryonic genome activation, and aberrant genomic methylation were found in preimplantation embryos derived from prepubertal lamb oocytes. Graphical Abstract

Infertility affects 8–12% of couples globally, and the male factor is a primary cause in ∼50% of couples. Male infertility is a multifactorial reproductive disorder, which can be caused by paracrine and autocrine factors, hormones, genes, and epigenetic changes. Recent studies in rodents and most notably in humans using multiomics approach have yielded important insights into understanding the biology of spermatogenesis. Nonetheless, the etiology and pathogenesis of male infertility are still largely unknown. In this review, we summarized and critically evaluated findings based on the use of advanced technologies to compare normal and obstructive azoospermic versus nonobstructive azoospermic men, including whole-genome bisulfite sequencing, single-cell RNA-seq, whole-exome sequencing, and transposase-accessible chromatin using sequencing. It is obvious that the multiomics approach is the method of choice for basic research and clinical studies including clinical diagnosis of male infertility. Summary Sentence This review summarizes findings of the past 20 years published in literature listed in PubMed including our laboratory, utilizing multiomics approach to study the etiology and pathogenesis of male infertility. Graphical Abstract

Background DNA methylation has a potential role in controlling gene expression and may, therefore, contribute to salinity adaptation in plants. Caliph medic ( Medicago truncatula ) is a model legume of moderate salinity tolerance capacity; however, a base-resolution DNA methylome map is not yet available for this plant. Results In this report, a differential whole-genome bisulfite sequencing (WGBS) was carried out using DNA samples extracted from root tissues exposed to either control or saline conditions. Around 50 million differentially methylated sites (DMSs) were recognized, 7% of which were significantly ( p  < 0.05, FDR  < 0.05) altered in response to salinity. This analysis showed that 77.0% of the contexts of DMSs were mCHH, while only 9.1% and 13.9% were mCHG and mCG, respectively. The average change in methylation level was increased in all sequence contexts, ranging from 3.8 to 10.2% due to salinity stress. However, collectively, the level of the DNA methylation in the gene body slightly decreased in response to salinity treatment. The global increase in DNA methylation due to salinity was confirmed by mass spectrometry analysis. Gene expression analysis using qPCR did not reveal a constant relationship between the level of mCG methylation and the transcription abundance of some genes of potential importance in salinity tolerance, such as the potassium channel KAT3, the vacuolar H + -pyrophosphatase (V-PPase), and the AP2/ERF and bZIP transcription factors, implying the involvement of other epigenetic gene expression controllers. Computational functional prediction of the annotated genes that embrace DMSs revealed the presence of enzymes with potential cellular functions in biological processes associated with salinity tolerance mechanisms. Conclusions The information obtained from this study illustrates the effect of salinity on DNA methylation and shows how plants can remodel the landscape of 5-methylcytosine nucleotide (5-mC) in the DNA across gene structures, in response to salinity. This remodeling varies between gene regions and between 5-mC sequence contexts. The mCG has a vague impact on the expression levels of a few selected potentially important genes in salt tolerant mechanisms.