BMC Genomics最新文献

Background: Brown adipose tissue (BAT) has a significant impact in newborn goats on maintaining body temperature through non-shivering thermogenesis in response to cold exposure. However, the roles of heat treatment on BAT thermogenesis are still limited.

Results: This study focused on the effects of short-term heat exposure on goat brown adipocytes. We found that the content of mitochondria and the proteins of UCP1 and PGC1α were increased after 12 h of heat exposure. Additionally, the triglyceride (TG) content was significantly decreased after 1, 2, 6 h of heat exposure. Furthermore, RNA-seq analysis of brown adipocytes after 12 h of heat exposure identified 1091 differentially expressed genes (DEGs). The KEGG enrichment analysis were mainly enriched in thermogenesis, fatty acid metabolism and mitophagy. In addition, we found that the amount of mitophagosomes and expression levels of mitophagy-related protein (LC3BII/LC3BI, BNIP3, and BECN) were elevated after 12 h of heat treatment.

Conclusion: These findings collectively indicate that heat exposure enhances the thermogenic capacity and mitophagy level of goat brown adipocytes. Our study provides evidence that heat exposure facilitates adaptive thermogenesis in goat brown adipocytes.

Runs of Homozygosity (ROH) are homozygous genomic fragments inherited from parents to offspring. ROH can be used to indicate the level of inbreeding, as well as to identify possible signatures of artificial or natural selection. Indigenous sheep populations on the southern edge of the Taklimakan Desert have evolved unique genetic traits adapted to extreme desert environments. In an attempt to better understand the adaptive mechanisms of these populations under harsh conditions, we used Illumina® Ovine SNP50K BeadChip to perform a genomic characterization of three recognized breeds (Duolang: n = 36, Hetian: n = 84, Qira black: n = 189) and one ecotypic breed (Kunlun: n = 27) in the region. Additionally, we assessed genomic inbreeding coefficients through ROH analysis, revealing insights into the inbreeding history of these populations. Subsequently, we retrieved candidate genes associated with economic traits in sheep from ROH islands in each breed. To better understand the autozygosity and distribution of ROH islands in these indigenous sheep breeds relative to international breeds, we also included three commercial mutton breeds (Poll Dorset: n = 108, Suffolk: n = 163, Texel: n = 150). The study revealed that among seven sheep breeds, Hetian exhibited the shortest linkage disequilibrium (LD) decay distance, while Kunlun demonstrated the highest LD levels. A total of 10,916 ROHs were obtained. The number of ROHs per breed ranged from 34 (Kunlun) to 2,826 (Texel). The length of ROH was mainly 1-5 Mb (63.54%). Furthermore, 991 candidate genes specific to indigenous sheep breeds were identified, including those associated with heat tolerance, adaptability, energy metabolism, reproduction, and immune response. These findings elucidate the genetic adaptation of indigenous sheep in the Taklimakan Desert, uncovering distinctive characteristics of indigenous sheep formation, and advocating for the conservation and genetic enhancement of local sheep populations.

Background: The complete dormancy release determines the quality of bud break, flowering and fruiting. While in tree peony (Paeonia suffruticosa Andr.), the insufficient accumulation of cold temperatures results in incomplete dormancy release and poor flowering quality.

Results: In order to investigate if phytohormone can replace the chilling requirement in south China and other similar regions, the roles of fluridone (Flu), gibberellin (GA₃), and their combination in the bud dormancy release process were analyzed. It demonstrated that the application of exogenous GA₃ and the mixture significantly expedited the dormancy release of tree peony at 23℃. Furthermore, the endogenous hormone levels provided evidence for the substantial impact of exogenous GA₃ on dormancy release, highlighting its potential involvement in the chilling-independent pathway of dormancy release. Transcriptome sequencing and analysis of expression profiles were conducted to identify the crucial genes implicated in the dormancy release mechanism of tree peony. Among numerous genes from diverse gene families, the particularly interesting were TEOSINTE BRANCHED 1, CYCLOIDEA, and PROLIFERATING CELL FACTORS-like genes (PsTCP3, PsTCP4, and PsTCP14), which had significant expression levels during the dormancy release process under different treatments. They were divided into two distinct sub-families based on their different domains. Specifically, PsTCP14 was classified under Class I, while PsTCP3 and PsTCP4 were classified under Class II. The analysis of expression patterns revealed a significant accumulation of the three PsTCPs in buds undergoing dormancy release, with clear upregulation observed in response to GA₃ and the mixture treatments. Additionally, the analysis of promoter activity demonstrated the sensitivity of PsTCP4 and PsTCP14 to GA₃ and Flu.

Conclusion: The application of exogenous GA₃ has been shown to effectively expedite the release of dormancy in tree peony through a pathway that is not dependent on chilling. Further research found that PsTCP genes might play a crucial role in this process. These findings contribute to the understanding of the molecular mechanism of PsTCPs in the hormone-mediated and temperature-independent release of bud dormancy in tree peony.

Background: Ducks are globally important poultry species and a major source of farm animal products, including meat, eggs, and feathers. A thorough understanding of the functional genomic and transcriptomic sequences is crucial for improving production efficiency.

Result: This study constructed the largest duck mRNA expression atlas among all waterfowl species to date. The atlas encompasses 1,257 tissue samples across 30 tissue types, representing all major organ systems. Using advanced clustering analysis, we established co-expression network clusters to describe the transcriptional features in the duck mRNA expression atlas and, when feasible, assign these features to unique tissue types or pathways. Additionally, we identified 27 low-variance, highly expressed housekeeping genes suitable for gene expression experiments. Furthermore, in-depth analysis revealed potential sex-biased gene expression patterns within tissues and specific gene expression profiles in meat-type and egg-type ducks, providing valuable resources to understand the genetic basis of sex differences and particular phenotypes. This research elucidates the biological processes affecting duck productivity.

Conclusion: This study presents the most extensive gene expression atlas for any waterfowl species to date. These findings are of significant value for advancing duck biological research and industrial applications.

Background: Transcription factors (TFs) regulate the genes' expression by binding to DNA sequences. Aligned TFBSs of the same TF are seen as cis-regulatory motifs, and substantial computational efforts have been invested to find motifs. In recent years, convolutional neural networks (CNNs) have succeeded in TF-DNA binding prediction, but existing DL methods' accuracy needs to be improved and convolution function in TF-DNA binding prediction should be further explored.

Results: We develop a cascaded convolutional neural network model named CacPred to predict TF-DNA binding on 790 Chromatin immunoprecipitation-sequencing (ChIP-seq) datasets and seven ChIP-nexus (chromatin immunoprecipitation experiments with nucleotide resolution through exonuclease, unique barcode, and single ligation) datasets. We compare CacPred to six existing DL models across nine standard evaluation metrics. Our results indicate that CacPred outperforms all comparison models for TF-DNA binding prediction, and the average accuracy (ACC), matthews correlation coefficient (MCC), and the area of eight metrics radar (AEMR) are improved by 3.3%, 9.2%, and 6.4% on 790 ChIP-seq datasets. Meanwhile, CacPred improves the average ACC, MCC, and AEMR of 5.5%, 16.8%, and 12.9% on seven ChIP-nexus datasets. To explain the proposed method, motifs are used to show features CacPred learned. In light of the results, CacPred can find some significant motifs from input sequences.

Conclusions: This paper indicates that CacPred performs better than existing models on ChIP-seq data. Seven ChIP-nexus datasets are also analyzed, and they coincide with results that our proposed method performs the best on ChIP-seq data. CacPred only is equipped with the convolutional algorithm, demonstrating that pooling processing of the existing models leads to losing some sequence information. Some significant motifs are found, showing that CacPred can learn features from input sequences. In this study, we demonstrate that CacPred is an effective and feasible model for predicting TF-DNA binding. CacPred is freely available at https://github.com/zhangsq06/CacPred .

Background: Linked-reads improve de novo assembly, haplotype phasing, structural variant (SV) detection, and other applications through highly-multiplexed genome partitioning and barcoding. Whole genome assembly and assembly-based variant detection based on linked-reads often require intensive computation costs and are not suitable for large population studies. Here we propose an efficient pipeline, RegionIndel, a region-based diploid assembly approach to characterize large indel SVs. This pipeline only focuses on target regions (50kb by default) to extract barcoded reads as input and then integrates a haplotyping algorithm and local assembly to generate phased diploid contiguous sequences (contigs). Finally, it detects variants in the contigs through a pairwise contig-to-reference comparison.

Results: We applied RegionIndel on two linked-reads libraries of sample HG002, one using 10x and the other stLFR. HG002 is a well-studied sample and the Genome in a Bottle (GiaB) community provides a gold standard SV set for it. RegionIndel outperformed several assembly and alignment-based SV callers in our benchmark experiments. After assembling all indel SVs, RegionIndel achieved an overall F1 score of 74.8% in deletions and 61.8% in insertions for 10x linked-reads, and 64.3% in deletions and 36.7% in insertions for stLFR linked-reads, respectively. Furthermore, it achieved an overall genotyping accuracy of 83.6% and 80.8% for 10x and stLFR linked-reads, respectively.

Conclusions: RegionIndel can achieve diploid assembly and detect indel SVs in each target region. The phased diploid contigs can further allow us to investigate indel SVs with nearby linked single nucleotide polymorphism (SNPs) and small indels in the same haplotype.

Background: Oocyte maturation is crucial for female fertility and embryonic development, encompassing nuclear and cytoplasmic maturation. Supportive cells of follicles, such as granulosa cells, are essential for oocyte growth and maturation. Oocytes can achieve nuclear maturation without granulosa cells during in vitro maturation (IVM). However, there is still a higher chance of incomplete cytoplasmic maturation for these oocytes with mature nuclei compared with oocytes cultured with granulosa cells. Oocytes with incomplete cytoplasmic maturation have lower fertilization rates and developmental potential than mature ones, although underlying mechanisms are poorly understood. Identifying key genes and signaling pathways associated with oocyte cytoplasmic maturation can help further elucidate the maturing process of oocytes and understand the impact of immature oocytes on embryonic development, throwing insights into the strategy to improve the success rate of assisted reproductive technologies.

Results: Our study investigated murine oocytes maturing with and without granulosa cells. IVM without granulosa cells yielded oocytes with lower nuclear maturation rates than IVM with granulosa cells and in vivo maturation (IVO). Even though oocytes could achieve nuclear maturation without granulosa cells, they showed incomplete cytoplasmic maturation featuring higher levels of reactive oxygen species, lower mitochondrial density, and higher proportions of cells with abnormal distributions of cortical granules. Of note, oocytes with immature and mature cytoplasm had distinct transcriptional profiles. In the immature oocytes, we observed a deficient mRNA restoration of genes in crucial regulatory pathways of cellular growth and division, potentially affecting embryonic development. Differentially expressed genes (DEGs) between immature and mature oocytes were identified to be highly expressed in different pre-implantation stages, such as the MII oocyte, the 8-cell stage, and the ICM stage. Identified DEGs were enriched in key regulatory pathways of fertilization and embryonic development, such as energy and metabolic pathways. These observations indicated that the impeded development potential of oocytes with immature cytoplasm might be the result of abnormal gene expressions during oocyte maturation.

Conclusions: We show that granulosa cells are important for both nuclear and cytoplasmic maturation of oocytes. Abnormal gene expression in oocytes with incomplete cytoplasmic maturation may be associated with potential defects in fertilization and embryonic development.

Understanding the mechanisms of early clearance of Mycobacterium tuberculosis (Mtb) may illuminate new therapeutic strategies for tuberculosis (TB). We previously found genetic, epigenetic, and transcriptomic signatures associated with resistance (resister, RSTR) to tuberculin skin test (TST)/interferon gamma release assay (IGRA) conversion among highly exposed TB contacts. We hypothesized that integration of these datasets with multi-omic latent factor methods would detect pathways differentiating RSTR patients from those with asymptomatic TB infection (TBI, also known as latent TB infection or LTBI) that were not detected in individual dataset analyses. We pre-filtered and scaled features with the largest change between TBI and RSTR groups for 126 patients with data in at least two of five data modalities: single nucleotide polymorphisms (SNP), monocyte RNAseq (baseline and Mtb-stimulated conditions), and monocyte epigenetics (methylation and ATAC-seq). Using multiomic latent factor analysis (MOFA), we generated ten latent factors on the subset of 33 patients with all five datasets available, four of which differed by RSTR status (FDR < 0.1). Factor 4 showed the greatest difference between RSTR and TBI groups (FDR < 0.001). Three additional latent factor integration methods also distinguished the RSTR and TBI groups and identified overlapping features with MOFA. Using pathway analysis and a cluster-based enrichment method, we identified functions associated with latent factors and found that MOFA Factors 2-4 include functions related to cell-cell adhesion, cell shape, and multicellular structure development. In summary, latent variable integration methods uncovered signatures associated with resistance to TST/IGRA conversion that were not detected by individual dataset analyses and included pathways associated with cellular interactions and multicellular structures.

Background: Fatty acid hydroxylases (FAHs) are a family of enzymes that includes fatty acid hydroxylases, carotenoid hydroxylases, and sterol desaturases. Fatty acids are highly important for plants. They are the main source of energy storage and the main component of the cell membrane. Saturated fatty acids can be divided into two categories: saturated fatty acids and unsaturated fatty acids. FAHs play a pivotal role in enhancing plant salt tolerance by modulating fatty acid metabolic pathways, thereby improving cell membrane stability and antioxidant capacity.

Results: In this study, we identified a total of 129 FAH gene family members in four cotton species, namely, Gossypium hirsutum, Gossypium darwinii, Gossypium arboreum, and Gossypium raimondii. The FAH genes were divided into five subgroups via evolutionary analysis. FAH genes located in the same subgroup presented similar gene structures and a consistent distribution of conserved motifs through the analysis of evolutionary trees, gene structures, and conserved motifs. Chromosomal localization analysis of the FAH gene family revealed that it has undergone chromosomal segment duplication events. Analysis of cis-acting elements suggested that the FAH gene may be involved in regulating biotic and abiotic stresses, plant growth and development, signaling pathways, and other physiological processes. The RT‒qPCR results revealed significant differences in the expression levels of FAH gene family members under salt stress conditions compared with those in the control group. Additionally, we successfully silenced Gohir.A03G045300 through VIGS experiments, and the results indicated that the silenced plants were more sensitive to salt stress than the control plants were. This suggests that Gohir.A03G045300 may be involved in the response of cotton to salt stress.

Conclusions: A total of 129 FAH genes were identified in four Gossypium species through bioinformatics analysis. Gene silencing of FAH members in G. hirsutum revealed that the FAH gene family plays a crucial role in the response of cotton to salt stress.