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Philippe Lefrançois, Beth Rockmill, Pingxing Xie, G Shirleen Roeder, Michael Snyder
During meiosis, chromosomes undergo a homology search in order to locate their homolog to form stable pairs and exchange genetic material. Early in prophase, chromosomes associate in mostly non-homologous pairs, tethered only at their centromeres. This phenomenon, conserved through higher eukaryotes, is termed centromere coupling in budding yeast. Both initiation of recombination and the presence of homologs are dispensable for centromere coupling (occurring in spo11 mutants and haploids induced to undergo meiosis) but the presence of the synaptonemal complex (SC) protein Zip1 is required...
October 2016: PLoS Genetics
Deepak Adhikari, Kiran Busayavalasa, Jingjing Zhang, Mengwen Hu, Sanjiv Risal, Mustafa Bilal Bayazit, Meenakshi Singh, M Kasim Diril, Philipp Kaldis, Kui Liu
A unique feature of female germ cell development in mammals is their remarkably long arrest at the prophase of meiosis I, which lasts up to 50 years in humans. Both dormant and growing oocytes are arrested at prophase I and completely lack the ability to resume meiosis. Here, we show that the prolonged meiotic arrest of female germ cells is largely achieved via the inhibitory phosphorylation of Cdk1 (cyclin-dependent kinase 1). In two mouse models where we have introduced mutant Cdk1(T14AY15F) which cannot be inhibited by phosphorylation (Cdk1AF) in small meiotically incompetent oocytes, the prophase I arrest is interrupted, leading to a premature loss of female germ cells...
October 21, 2016: Cell Research
Delphine Mieulet, Sylvie Jolivet, Maud Rivard, Laurence Cromer, Aurore Vernet, Pauline Mayonove, Lucie Pereira, Gaëtan Droc, Brigitte Courtois, Emmanuel Guiderdoni, Raphael Mercier
Introduction of clonal reproduction through seeds (apomixis) in crops has the potential to revolutionize agriculture by allowing self-propagation of any elite variety, in particular F1 hybrids. In the sexual model plant Arabidopsis thaliana synthetic clonal reproduction through seeds can be artificially implemented by (i) combining three mutations to turn meiosis into mitosis (MiMe) and (ii) crossing the obtained clonal gametes with a line expressing modified CENH3 and whose genome is eliminated in the zygote...
October 21, 2016: Cell Research
Irina Trofimova, Alla Krasikova
Tandemly organized highly repetitive DNA sequences are crucial structural and functional elements of eukaryotic genomes. Despite extensive evidence, satellite DNA remains an enigmatic part of the eukaryotic genome, with biological role and significance of tandem repeat transcripts remaining rather obscure. Data on tandem repeats transcription in amphibian and avian model organisms is fragmentary despite their genomes being thoroughly characterized. Review systematically covers historical and modern data on transcription of amphibian and avian satellite DNA in somatic cells and during meiosis when chromosomes acquire special lampbrush form...
October 20, 2016: RNA Biology
Ru-Xia Jia, Xing Duan, Si-Jing Song, Shao-Chen Sun
LIMKi 3 is a specific selective LIMK inhibitor against LIMK1 and LIMK2, while LIMK1 and LIMK2 are the main regulators of actin cytoskeleton to participate in many cell activities. However, the effect of LIMKi 3 in porcine oocyte meiosis is still unclear. The present study was designed to investigate the effects of LIMKi 3 and potential regulatory role of LIMK1/2 on porcine oocyte meiotic maturation. Immunofluorescent staining of p-LIMK1/2 antibody showed that LIMK1/2 was localized mainly to the cortex of porcine oocyte, which co-localized with actin...
2016: PeerJ
Miguel A Brieño-Enríquez, Stefannie L Moak, Melissa Toledo, Joshua J Filter, Stephen Gray, José L Barbero, Paula E Cohen, J Kim Holloway
Mammalian NIMA-like kinase-1 (NEK1) is a dual-specificity kinase highly expressed in mouse germ cells during prophase I of meiosis. Loss of NEK1 induces retention of cohesin on chromosomes at meiotic prophase I. Timely deposition and removal of cohesin is essential for accurate chromosome segregation. Two processes regulate cohesin removal: a non-proteolytic mechanism involving WAPL, sororin, and PDS5B and direct cleavage by separase. Here, we demonstrate a role for NEK1 in the regulation of WAPL loading during meiotic prophase I, via an interaction between NEK1 and PDS5B...
October 18, 2016: Cell Reports
Kris G Alavattam, Yasuko Kato, Ho-Su Sin, So Maezawa, Ian J Kowalski, Fan Zhang, Qishen Pang, Paul R Andreassen, Satoshi H Namekawa
Precise epigenetic regulation of the sex chromosomes is vital for the male germline. Here, we analyze meiosis in eight mouse models deficient for various DNA damage response (DDR) factors, including Fanconi anemia (FA) proteins. We reveal a network of FA and DDR proteins in which FA core factors FANCA, FANCB, and FANCC are essential for FANCD2 foci formation, whereas BRCA1 (FANCS), MDC1, and RNF8 are required for BRCA2 (FANCD1) and SLX4 (FANCP) accumulation on the sex chromosomes during meiosis. In addition, FA proteins modulate distinct histone marks on the sex chromosomes: FA core proteins and FANCD2 regulate H3K9 methylation, while FANCD2 and RNF8 function together to regulate H3K4 methylation independently of FA core proteins...
October 18, 2016: Cell Reports
Friederike Finsterbusch, Ramya Ravindranathan, Ihsan Dereli, Marcello Stanzione, Daniel Tränkner, Attila Tóth
Orderly chromosome segregation during the first meiotic division requires meiotic recombination to form crossovers between homologous chromosomes (homologues). Members of the minichromosome maintenance (MCM) helicase family have been implicated in meiotic recombination. In addition, they have roles in initiation of DNA replication, DNA mismatch repair and mitotic DNA double-strand break repair. Here, we addressed the function of MCMDC2, an atypical yet conserved MCM protein, whose function in vertebrates has not been reported...
October 2016: PLoS Genetics
Suzanne Vigneron, Perle Robert, Khaled Hached, Lena Sundermann, Sophie Charrasse, Jean-Claude Labbé, Anna Castro, Thierry Lorca
Entry into mitosis requires the coordinated activation of various protein kinases and phosphatases that together activate sequential signaling pathways allowing entry, progression and exit of mitosis. The limiting step is thought to be the activation of the mitotic Cdk1-cyclin B kinase. However, this model has recently evolved with new data showing that in addition to the Cdk1-cyclin B complex, Greatwall (Gwl) kinase is also required to enter into and maintain mitosis. This new concept proposes that entry into mitosis is now based on the combined activation of both kinases Cdk1-cyclin B and Gwl, the former promoting massive phosphorylation of mitotic substrates and the latter inhibiting PP2A-B55 phosphatase responsible for dephosphorylation of these substrates...
2016: International Journal of Developmental Biology
Zhanzhan Xu, Yu Zhou, Yexuan Cao, Thi Lan Anh Dinh, Jing Wan, Min Zhao
Ovarian cancer is the first leading cause of mortality in gynecological malignancies. To identify key genes and microRNAs in ovarian cancer, mRNA microarray dataset GSE36668, GSE18520, GSE14407 and microRNA dataset GSE47841 were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and microRNAs (DEMs) were obtained using GEO2R. Functional and pathway enrichment analysis were performed for DEGs using DAVID database. Protein-protein interaction (PPI) network was established by STRING and visualized by Cytoscape...
November 2016: Medical Oncology
Mayu Horie, Tomoya Kotani
Many translationally repressed mRNAs are deposited in the oocyte cytoplasm for progression of the meiotic cell cycle and early development. mos and cyclin B1 mRNAs encode proteins promoting oocyte meiosis, and translational control of these mRNAs is important for normal progression of meiotic cell division. We previously demonstrated that cyclin B1 mRNA forms RNA granules in the zebrafish and mouse oocyte cytoplasm and that the formation of RNA granules is crucial for regulating the timing of translational activation of the mRNA...
October 4, 2016: European Journal of Cell Biology
Soledad Sagastume, Raquel Martín-Hernández, Mariano Higes, Nuno Henriques-Gil
BACKGROUND: There is great controversy as to whether Microsporidia undergo a sexual cycle. In the paradigmatic case of Nosema ceranae, although there is no morphological evidence of sex, some meiosis-specific genes are present in its reduced genome and there is also high intraspecific variability, with incongruent phylogenies having been systematically obtained. The possibility of sexual recombination is important from an epidemiological standpoint, particularly as N. ceranae is considered to be a major factor in the current disquieting epidemic of widespread bee colony losses...
October 18, 2016: BMC Evolutionary Biology
Yasuhiro Matsuo, Makoto Kawamukai
The cAMP-dependent protein kinase Pka1 is known as a regulator of glycogenesis, meiosis, and stress responses in Schizosaccharomyces pombe. We demonstrated that Pka1 is responsible for calcium tolerance. Loss of functional components of the PKA pathway such as Git3, Gpa2, Cyr1, and Pka1 yields a CaCl2-sensitive phenotype, while loss of Cgs1, a regulatory subunit of PKA, results in CaCl2 tolerance. Cytoplasmic distribution of Cgs1 and Pka1 is increased by the addition of CaCl2, suggesting that CaCl2 induces dissociation of Cgs1 and Pka1...
October 19, 2016: Bioscience, Biotechnology, and Biochemistry
Fereshteh Esfandiari, Mohammad Kazemi Ashtiani, Mehdi Sharifi-Tabar, Maryam Saber, Hamed Daemi, Mohammad Hossein Ghanian, Abdolhossein Shahverdi, Hossein Baharvand
Producing meiosis-competent germ cells (GCs) from embryonic stem cells (ESCs) is essential for developing advanced therapies for infertility. Here, a novel approach is presented for generation of GCs from ESCs. In this regard, microparticles (MPs) have been developed from alginate sulfate loaded with bone morphogenetic protein 4 (BMP4). The results here show that BMP4 release from alginate sulfate MPs is significantly retarded by the sulfated groups compared to neat alginate. Then, BMP4-laden MPs are incorporated within the aggregates during differentiation of GCs from ESCs...
October 17, 2016: Macromolecular Bioscience
Julyun Oh, Amr Al-Zain, Elda Cannavo, Petr Cejka, Lorraine S Symington
The Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex orchestrates the cellular response to DSBs through its structural, enzymatic, and signaling roles. Xrs2/Nbs1 is essential for nuclear translocation of Mre11, but its role as a component of the complex is not well defined. Here, we demonstrate that nuclear localization of Mre11 (Mre11-NLS) is able to bypass several functions of Xrs2, including DNA end resection, meiosis, hairpin resolution, and cellular resistance to clastogens. Using purified components, we show that the MR complex has equivalent activity to MRX in cleavage of protein-blocked DNA ends...
October 20, 2016: Molecular Cell
D F Dubeibe, M C Caldas-Bussiere, V L Maciel, W V Sampaio, C R Quirino, P B D Gonçalves, M P De Cesaro, M R Faes, C S Paes de Carvalho
Nitric oxide (NO) is identified as a signaling molecule involved in many cellular or physiological functions, including meiotic maturation of cattle oocytes. This study aimed to evaluate the effect of supplementation of culture medium with the L-arginine (L-arg, NO synthesis precursor) in nuclear maturation of oocytes, concentrations of nitrate/nitrite, progesterone (P4), and 17β-estradiol (E2) in the culture medium; and the cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) intracellular concentrations in the cumulus-oocyte complexes (COCs) during the first hours of maturation in the presence of hemisections (HSs) of the follicular wall (control -ve)...
September 17, 2016: Theriogenology
Yunhui Li, Minhui Zhang, Shaojun Li, Rongrong Lv, Pan Chen, Ran Liu, Geyu Liang, Lihong Yin
There is increasing evidence that epoxiconazole exposure can affect reproductive function, but few studies have investigated adverse effects on spermatogenesis. The nematode Caenorhabditis elegans (C. elegans) was used in our study to assess effects of epoxiconazole on spermatogenesis in male nematodes after 48 h of exposure to concentrations of 0.1, 1.0, or 10.0 μg/L. The results demonstrated that epoxiconazole exposure affected spermatogenesis, decreasing the number of total germ cells, mitotic cells, meiotic cells and spermatids, spermatid diameter, and cross-sectional area, and inducing mitotic germ cell proliferation arrest, premature entry into meiosis, and sperm activation inhibition; however, sperm transfer showed no abnormal changes...
October 8, 2016: International Journal of Environmental Research and Public Health
Lili Ni, Hongchang Xie, Li Tan
The transcription factor FOXJ3 (Forkhead box J3) is highly expressed in spermatogonia and meiotic spermatocytes within mouse testes. Here, we addressed how FOXJ3 might participate in spermatogenesis using two conditional knockout mouse models in which the Foxj3 was deleted from either spermatogonia or meiotic spermatocytes. Both models exhibited complete male sterility, but distinct etiologies: Deleting FOXJ3 from spermatogonia using Foxj3(flox/flox) , Mvh-Cre mice caused Sertoli-cell-only syndrome in males...
October 14, 2016: Molecular Reproduction and Development
Xiaojie Yang, Yuanming Zhao, Deyi Xie, Yao Sun, Xunlu Zhu, Nardana Esmaeili, Zuoren Yang, Ye Wang, Guo Yin, Shuping Lv, Lihong Nie, Zhongjie Tang, Fu'an Zhao, Wu Li, Neelam Mishra, Li Sun, Wei Zhu, Weiping Fang
Hybrid vigor contributes in a large way to the yield and quality of cotton (Gossypium hirsutum) fiber. Although microRNAs play essential regulatory roles in flower induction and development, it is still unclear if microRNAs are involved in male sterility, as the regulatory molecular mechanisms of male sterility in cotton need to be better defined. In this study, two independent small RNA libraries were constructed and sequenced from the young buds collected from the sporogenous cell formation to the meiosis stage of the male sterile line Yu98-8A and the near-isogenic line...
October 7, 2016: International Journal of Molecular Sciences
Takamasa Hirano, Hidetoshi Hasuwa, Haruhiko Siomi
The mouse testis has served as a popular model system to study a wide range of biological processes, including germ cell development, meiosis, epigenetic changes of chromatin, transposon silencing, and small RNA-mediated epigenetic modifications. PIWI-interacting RNAs (piRNAs) are a class of small RNAs that are almost exclusively expressed in animal gonads. They repress transposons by forming effector complexes with PIWI proteins to maintain genome integrity of the germline. Here we describe detailed procedures of how to produce monoclonal antibodies against a mouse nuclear PIWI protein, MIWI2, which functions in de novo DNA methylation of target transposon loci...
2017: Methods in Molecular Biology
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