Histone modification and nucleosome assembly play important roles in chromatin-related processes.Histone chaperones form different complexes and coordinate histone transportation and assembly.Various histone chaperone complexes have been identified in different organisms.The ciliate protozoa(ciliates)have various chromatin structures and different nuclear morphology.However,histone chaperone components and functions of different subunits remain unclear in ciliates.Tet-rahymema thermophila contains a transcriptionally active macronucleus(MAC)and a transcriptionally inactive micronu-cleus(MIC)which exhibit multiple replication and various chromatin remodeling progresses during vegetative growth and sexual developmental stages.Here,we found histone chaperone RebL1 not only localized evenly in the transcriptionally active MAC but also dynamically changed in the MIC during vegetative growth and sexual developmental stages.REBL1 knockdown inhibited cellular proliferation.The macronuclear morphology became bigger in growing mutants.The abnormal macronuclear structure also occurred in the starvation stage.Furthermore,micronuclear meiosis was disturbed during sexual development,leading to a failure to generate new gametic nuclei.RebL1 potentially interacted with various factors involved in histone-modifying complexes and chromatin remodeling complexes in different developmental stages.REBL1 knockdown affected expression levels of the genes involved in chromatin organization and transcription.Taken together,RebL1 plays a vital role in maintaining macronuclear structure stability and gametogenesis in T.thermophila.
Huijuan HaoYinjie LianChenhui RenSitong YangMin ZhaoTao BoJing XuWei Wang
Gametogenesis plays an important role in the reproduction and evolution of species.The transcriptomic and epigenetic alterations in this process can influence the reproductive capacity,fertilization,and embryonic development.The rapidly increasing single-cell studies have provided valuable multi-omics resources.However,data from different layers and sequencing platforms have not been uniformed and integrated,which greatly limits their use for exploring the molecular mechanisms that underlie oogenesis and spermatogenesis.Here,we develop GametesOmics,a comprehensive database that integrates the data of gene expression,DNA methylation,and chromatin accessibility during oogenesis and spermatogenesis in humans and mice.GametesOmics provides a user-friendly website and various tools,including Search and Advanced Search for querying the expression and epigenetic modification(s)of each gene;Tools with Differentially expressed gene(DEG)analysis for identifying DEGs,Correlation analysis for demonstrating the genetic and epigenetic changes,Visualization for displaying single-cell clusters and screening marker genes as well as master transcription factors(TFs),and MethylView for studying the genomic distribution of epigenetic modifications.GametesOmics also provides Genome Browser and Ortholog for tracking and comparing gene expression,DNA methylation,and chromatin accessibility between humans and mice.GametesOmics offers a comprehensive resource for biologists and clinicians to decipher the cell fate transition in germ cell development,and can be accessed at http://gametesomics.cn/.
As a defense mechanism against transposable elements,the PIWI-interacting RNA(piRNA)pathway maintains genomic integrity and ensures proper gametogenesis in gonads.Numerous factors are orchestrated to ensure normal operation of the piRNA pathway.Spindle-E(Spn-E)gene was one of the first genes shown to participate in the piRNA pathway.In this study,we performed functional analysis of Spn-E in the model lepidopteran insect,Bombyx mori.Unlike the germline-specific expression pattern observed in Drosophila and mouse,BmSpn-E was ubiquitously expressed in all tissues tested,and it was highly expressed in gonads.Immunofluorescent staining showed that BmSpn-E was localized in both germ cells and somatic cells in ovary and was expressed in spermatocytes in testis.We used a binary transgenic CRISPR/Cas9 system to construct BmSpn-E mutants.Loss of BmSpn-E expression caused derepression of transposons in gonads.We also found that mutant gonads were much smaller than wild-type gonads and that the number of germ cells was considerably lower in mutant gonads.Quantitative real-time PCR analysis and TUNEL staining revealed that apoptosis was greatly enhanced in mutant gonads.Further,we found that the BmSpn-E mutation impacted gonadal development and gametogenesis at the early larval stage.In summary,our data provided the first evidence that BmSpn-E plays vital roles in gonadal development and gametogenesis in B.mori.
In vitro gametogenesis(IVG)has been a topic of great interest in recent years not only because it allows for further exploration of mechanisms of germ cell development,but also because of its prospect for innovative medical applications especially for the treatment of infertility.Elucidation of the mechanisms underlying gamete development in vivo has inspired scientists to attempt to recapitulate the entire process of gametogenesis in vitro.While earlier studies have established IVG methods largely using pluripotent stem cells of embryonic origin,the scarcity of sources for these cells and the ethical issues involved in their use are serious limitations to the progress of IVG research especially in humans.However,with the emergence of induced pluripotent stem cells(iPSCs)due to the revolutionary discovery of dedifferentiation and reprogramming factors,IVG research has progressed remarkably in the last decade.This paper extensively reviews developments in IVG using iPSCs.First,the paper presents key concepts from groundwork studies on IVG including earlier researches demonstrating that IVG methods using embryonic stem cells(ESCs)also apply when using iPSCs.Techniques for the derivation of iPSCs are briefly discussed,highlighting the importance of generating transgene-free iPSCs with a high capacity for germline transmission to improve efficacy when used for IVG.The main part of the paper discusses recent advances in IVG research using iPSCs in various stages of gametogenesis.In addition,current clinical applications of IVG are presented,and potential future applications are discussed.Although IVG is still faced with many challenges in terms of technical issues,as well as efficacy and safety,novel IVG methodologies are emerging,and IVG using iPSCs may usher in the next era of reproductive medicine sooner than expected.This raises both ethical and social concerns and calls for the scientific community to cautiously develop IVG technology to ensure it is not only efficacious but also safe and adheres to social and et