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Nature Communications May 2024In plants, small-interfering RNAs (siRNAs) mediate epigenetic silencing via the RNA-directed DNA methylation (RdDM) pathway, which is particularly prominent during...
In plants, small-interfering RNAs (siRNAs) mediate epigenetic silencing via the RNA-directed DNA methylation (RdDM) pathway, which is particularly prominent during reproduction and seed development. However, there is limited understanding of the origins and dynamics of reproductive siRNAs acting in different cellular and developmental contexts. Here, we used the RNaseIII-like protein RTL1 to suppress siRNA biogenesis in Arabidopsis pollen, and found distinct siRNA subsets produced during pollen development. We demonstrate that RTL1 expression in the late microspore and vegetative cell strongly impairs epigenetic silencing, and resembles RdDM mutants in their ability to bypass interploidy hybridization barriers in the seed. However, germline-specific RTL1 expression did not impact transgenerational inheritance of triploid seed lethality. These results reveal the existence of multiple siRNA subsets accumulated in mature pollen, and suggest that mobile siRNAs involved in the triploid block are produced in germline precursor cells after meiosis, or in the vegetative cell during pollen mitosis.
Topics: Pollen; Arabidopsis; RNA, Small Interfering; Arabidopsis Proteins; Seeds; Gene Expression Regulation, Plant; Triploidy; DNA Methylation; Meiosis; Ribonuclease III; Epigenesis, Genetic
PubMed: 38816386
DOI: 10.1038/s41467-024-48950-6 -
Journal of Biomedical Optics Jun 2024Preparation of a recipient cytoplast by oocyte enucleation is an essential task for animal cloning and assisted reproductive technologies in humans. The femtosecond...
SIGNIFICANCE
Preparation of a recipient cytoplast by oocyte enucleation is an essential task for animal cloning and assisted reproductive technologies in humans. The femtosecond laser is a precise and low-invasive tool for oocyte enucleation, and it should be an appropriate alternative to traditional enucleation by a microneedle aspiration. However, until recently, the laser enucleation was performed only with applying a fluorescent dye.
AIM
This work is aimed to (1) achieve femtosecond laser oocyte enucleation without applying a fluorescent dye and (2) to study the effect of laser destruction of chromosomes on the structure and dynamics of the spindle.
APPROACH
We applied polarized light microscopy for spindle visualization and performed stain-free mouse and human oocyte enucleation with a 1033 nm femtosecond laser. Also, we studied transformation of a spindle after metaphase plate elimination by a confocal microscopy.
RESULTS
We demonstrated a fundamental possibility of inactivating the metaphase plate in mouse and human oocytes by 1033 nm femtosecond laser radiation without applying a fluorescent dye. Irradiation of the spindle area, visualized by polarized light microscopy, resulted in partly or complete metaphase plate destruction but avoided the microtubules impairment. After the metaphase plate elimination, the spindle reorganized, however, it was not a complete depolymerization.
CONCLUSIONS
This method of recipient cytoplast preparation is expected to be useful for animal cloning and assisted reproductive technologies.
Topics: Animals; Mice; Oocytes; Humans; Female; Lasers; Spindle Apparatus; Microscopy, Confocal; Metaphase; Microscopy, Polarization
PubMed: 38812963
DOI: 10.1117/1.JBO.29.6.065002 -
Brazilian Journal of Medical and... 2024Adenine nucleotide translocator 4 (Ant4), an ATP/ADP transporter expressed in the early phases of spermatogenesis, plays a crucial role in male fertility. While Ant4...
Adenine nucleotide translocator 4 (Ant4), an ATP/ADP transporter expressed in the early phases of spermatogenesis, plays a crucial role in male fertility. While Ant4 loss causes early arrest of meiosis and increased apoptosis of spermatogenic cells in male mice, its other potential functions in male fertility remain unexplored. Here, we utilized Ant4 knockout mice to delineate the effects of Ant4-deficiency on male reproduction. Our observations demonstrated that Ant4-deficiency led to infertility and impaired testicular development, which was further investigated by evaluating testicular oxidative stress, autophagy, and inflammation. Specifically, the loss of Ant4 led to an imbalance of oxidation and antioxidants. Significant ultrastructural alterations were identified in the testicular tissues of Ant4-deficient mice, including swelling of mitochondria, loss of cristae, and accumulation of autophagosomes. Our results also showed that autophagic flux and AKT-AMPK-mTOR signaling pathway were affected in Ant4-deficient mice. Moreover, Ant4 loss increased the expression of pro-inflammatory factors. Overall, our findings underscored the importance of Ant4 in regulating oxidative stress, autophagy, and inflammation in testicular tissues. Taken together, these insights provided a nuanced understanding of the significance of Ant4 in testicular development.
Topics: Animals; Male; Mice, Knockout; Testis; Oxidative Stress; Mitochondrial ADP, ATP Translocases; Mice; Autophagy; Infertility, Male; Spermatogenesis; Apoptosis; Signal Transduction
PubMed: 38808891
DOI: 10.1590/1414-431X2024e13590 -
Journal of Biomedical Research Apr 2024Microtubule-severing enzymes (MTSEs) play important roles in mitosis and meiosis of the primitive organisms. However, no studies have assessed their roles in mammalian...
Microtubule-severing enzymes (MTSEs) play important roles in mitosis and meiosis of the primitive organisms. However, no studies have assessed their roles in mammalian meiosis of females, whose abnormality accounts for over 80% of the cases of gamete-originated human reproductive disease. In the current study, we reported that katanin-like 2 (KL2) was the only MTSE concentrating at chromosomes. Furthermore, the knockdown of significantly reduced chromosome-based increase in the microtubule (MT) polymer, increased aberrant kinetochore-MT (K-MT) attachment, delayed meiosis, and severely affected normal fertility. Importantly, we demonstrated that the inhibition of aurora B, a key kinase for correcting aberrant K-MT attachment, eliminated KL2 from chromosomes completely. KL2 also interacted with phosphorylated eukaryotic elongation factor-2 kinase; they competed for chromosome binding. We also observed that the phosphorylated KL2 was localized at spindle poles, and that KL2 phosphorylation was regulated by extracellular signal-regulated kinase 1/2. In summary, our study reveals a novel function of MTSEs in mammalian female meiosis and demonstrates that multiple kinases coordinate to regulate the levels of KL2 at chromosomes.
PubMed: 38808565
DOI: 10.7555/JBR.37.20230290 -
Life Science Alliance Aug 2024Homologous recombination is a major pathway for the repair of DNA double strand breaks, essential both to maintain genomic integrity and to generate genetic diversity....
Homologous recombination is a major pathway for the repair of DNA double strand breaks, essential both to maintain genomic integrity and to generate genetic diversity. Mechanistically, homologous recombination involves the use of a homologous DNA molecule as a template to repair the break. In eukaryotes, the search for and invasion of the homologous DNA molecule is carried out by two recombinases, RAD51 in somatic cells and RAD51 and DMC1 in meiotic cells. During recombination, the recombinases bind overhanging single-stranded DNA ends to form a nucleoprotein filament, which is the active species in promoting DNA invasion and strand exchange. RAD51 and DMC1 carry two major DNA-binding sites-essential for nucleofilament formation and DNA strand exchange, respectively. Here, we show that the function of RAD51 DNA-binding site II is conserved in the plant, Arabidopsis. Mutation of three key amino acids in site II does not affect RAD51 nucleofilament formation but inhibits its recombinogenic activity, analogous to results from studies of the yeast and human proteins. We further confirm that recombinogenic function of RAD51 DNA-binding site II is not required for meiotic double-strand break repair when DMC1 is present. The Arabidopsis separation of function mutant shows a dominant negative phenotype, pointing to distinct biochemical properties of eukaryotic RAD51 proteins.
Topics: Arabidopsis; Rad51 Recombinase; Arabidopsis Proteins; Binding Sites; Homologous Recombination; Mutation; DNA Breaks, Double-Stranded; DNA-Binding Proteins; Meiosis; Cell Cycle Proteins; DNA Repair
PubMed: 38803223
DOI: 10.26508/lsa.202402701 -
Molecular Aspects of Medicine Jun 2024Meiosis is a critical step for spermatogenesis and oogenesis. Meiosis commences with pre-meiotic S phase that is subsequently followed by meiotic prophase. The meiotic... (Review)
Review
Meiosis is a critical step for spermatogenesis and oogenesis. Meiosis commences with pre-meiotic S phase that is subsequently followed by meiotic prophase. The meiotic prophase is characterized by the meiosis-specific chromosomal events such as chromosome recombination and homolog synapsis. Meiosis initiator (MEIOSIN) and stimulated by retinoic acid gene 8 (STRA8) initiate meiosis by activating the meiotic genes by installing the meiotic prophase program at pre-meiotic S phase. This review highlights the mechanisms of meiotic initiation and meiotic prophase progression from the point of the gene expression program and its relevance to infertility. Furthermore, upstream pathways that regulate meiotic initiation will be discussed in the context of spermatogenic development, indicating the sexual differences in the mode of meiotic entry.
Topics: Spermatogenesis; Humans; Meiosis; Animals; Male; Meiotic Prophase I; Prophase
PubMed: 38797021
DOI: 10.1016/j.mam.2024.101282 -
Genomics Jul 2024Hybrid sterility, a hallmark of postzygotic isolation, arises from parental genome divergence disrupting meiosis. While chromosomal incompatibility is often implicated,...
Hybrid sterility, a hallmark of postzygotic isolation, arises from parental genome divergence disrupting meiosis. While chromosomal incompatibility is often implicated, the underlying mechanisms remain unclear. This study investigated meiotic behavior and genome-wide divergence in bighead catfish (C. macrocephalus), North African catfish (C. gariepinus), and their sterile male hybrids (important in aquaculture). Repetitive DNA analysis using bioinformatics and cytogenetics revealed significant divergence in satellite DNA (satDNA) families between parental species. Notably, one hybrid exhibited successful meiosis and spermatozoa production, suggesting potential variation in sterility expression. Our findings suggest that genome-wide satDNA divergence, rather than chromosome number differences, likely contributes to meiotic failure and male sterility in these catfish hybrids.
Topics: Animals; Catfishes; Male; Meiosis; DNA, Satellite; Hybridization, Genetic; Infertility, Male; Genome; North African People
PubMed: 38795738
DOI: 10.1016/j.ygeno.2024.110868 -
Pharmaceuticals (Basel, Switzerland) May 2024Previously, we analyzed 316 herbal extracts to evaluate their potential nematocidal properties in In this study, our attention was directed towards ., resulting in...
Previously, we analyzed 316 herbal extracts to evaluate their potential nematocidal properties in In this study, our attention was directed towards ., resulting in reduced survival and heightened larval arrest/lethality, alongside a noticeable decrease in DAPI-stained bivalent structures and disrupted meiotic progression, thus disrupting developmental processes. Notably, . extracts activated a DNA damage checkpoint response via the ATM/ATR and CHK-1 pathways, hindering germline development. LC-MS analysis revealed 13 compounds in the . extracts, including flavonoids, terpenoids, tanshinones, an analog of resveratrol, iridoids, carotenoids, fatty acids, and alkaloids. Of these, 10 are known for their antitumor activity, suggesting the potential of beyond traditional gardening, extending into pharmaceutical and therapeutic applications.
PubMed: 38794181
DOI: 10.3390/ph17050611 -
Journal of Fungi (Basel, Switzerland) May 2024, one of the conidiation center regulatory genes in many filamentous fungi, plays an important role in promoting asexual spores (conidia) maturation. Our recent research...
, one of the conidiation center regulatory genes in many filamentous fungi, plays an important role in promoting asexual spores (conidia) maturation. Our recent research has found that knocking out or overexpressing (a homolog of ) in M7 does not affect the development of its asexual spores like other fungi, but both repress the development of its sexual spores (ascospores). However, the mechanism remains unclear. In this study, the function of on sexual reproduction and secondary metabolism in M7 was confirmed by a complementary experiment. Moreover, the regulatory roles of in modulating the expression of genes involved in sexual reproduction, meiosis, and biosynthesis of pigment and citrinin were analyzed based on the transcriptional data. These results not only contribute to clarifying the regulation of the reproduction and secondary metabolism of spp., but also to enriching the regulation molecular mechanism of reproduction in filamentous fungi.
PubMed: 38786694
DOI: 10.3390/jof10050338 -
Cells May 2024Mammalian oocyte development depends on the temporally controlled translation of maternal transcripts, particularly in the coordination of meiotic and early embryonic...
Mammalian oocyte development depends on the temporally controlled translation of maternal transcripts, particularly in the coordination of meiotic and early embryonic development when transcription has ceased. The translation of mRNA is regulated by various RNA-binding proteins. We show that the absence of cytoplasmic polyadenylation element-binding protein 3 (CPEB3) negatively affects female reproductive fitness. CPEB3-depleted oocytes undergo meiosis normally but experience early embryonic arrest due to a disrupted transcriptome, leading to aberrant protein expression and the subsequent failure of embryonic transcription initiation. We found that CPEB3 stabilizes a subset of mRNAs with a significantly longer 3'UTR that is enriched in its distal region with cytoplasmic polyadenylation elements. Overall, our results suggest that CPEB3 is an important maternal factor that regulates the stability and translation of a subclass of mRNAs that are essential for the initiation of embryonic transcription and thus for embryonic development.
Topics: Oocytes; Animals; RNA-Binding Proteins; Female; Mice; Meiosis; RNA, Messenger; Embryonic Development; Gene Expression Regulation, Developmental; 3' Untranslated Regions; Polyadenylation; RNA Stability
PubMed: 38786074
DOI: 10.3390/cells13100850