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M Charpentier, A H Y Khedher, S Menoret, A Brion, K Lamribet, E Dardillac, C Boix, L Perrouault, L Tesson, S Geny, A De Cian, J M Itier, I Anegon, B Lopez, C Giovannangeli, J P Concordet
In genome editing with CRISPR-Cas9, transgene integration often remains challenging. Here, we present an approach for increasing the efficiency of transgene integration by homology-dependent repair (HDR). CtIP, a key protein in early steps of homologous recombination, is fused to Cas9 and stimulates transgene integration by HDR at the human AAVS1 safe harbor locus. A minimal N-terminal fragment of CtIP, designated HE for HDR enhancer, is sufficient to stimulate HDR and this depends on CDK phosphorylation sites and the multimerization domain essential for CtIP activity in homologous recombination...
March 19, 2018: Nature Communications
Izumi Oda-Ishii, Tetsuya Abe, Yutaka Satou
In animal embryos, transcription is repressed for a definite period of time after fertilization. In the embryo of the ascidian, Ciona intestinalis (type A; or Ciona robusta), transcription of regulatory genes is repressed before the 8- or 16-cell stages. This initial transcriptional quiescence is important to enable the establishment of initial differential gene expression patterns along the animal-vegetal axis by maternal factors, because the third cell division separates the animal and vegetal hemispheres into distinct blastomeres...
March 14, 2018: Developmental Biology
Jason Z Morris
I have argued that substance ontology cannot be used to determine the moral status of embryos. Patrick Lee, Christopher Tollefsen, and Robert George wrote a Reply to those arguments in this Journal. In that Reply, Lee, Tollefsen, and George defended and clarified their position that their substance ontology arguments prove that the zygote and the adult into which it develops are the same entity that share the same essence. Here, I show the following: (A) Even using the substance ontology framework to which Lee, Tollefsen, and George subscribe, we cannot know when in development substance changes cease...
March 13, 2018: Journal of Medicine and Philosophy
Lanlin Yang, Sufen Cai, Shuoping Zhang, Xiangyi Kong, Yifan Gu, Changfu Lu, Jing Dai, Fei Gong, Guangxiu Lu, Ge Lin
STUDY QUESTION: Does single cleavage-stage (Day 3) embryo transfer using a time-lapse (TL) hierarchical classification model achieve comparable ongoing pregnancy rates (OPR) to single blastocyst (Day 5) transfer by conventional morphological (CM) selection? SUMMARY ANSWER: Day 3 single embryo transfer (SET) with a hierarchical classification model had a significantly lower OPR compared with Day 5 SET with CM selection. WHAT IS KNOWN ALREADY: Cleavage-stage SET is an alternative to blastocyst SET...
March 13, 2018: Human Reproduction
Qingqing Wei, Ruiqi Li, Liang Zhong, Haiyuan Mu, Shaopeng Zhang, Liang Yue, Jinzhu Xiang, Enhong Li, Minglei Zhi, Suying Cao, Jianyong Han
After zygotic genome activation and lineage specification, zygotes develop into late blastocysts comprising three distinct cell types. The molecular mechanisms underlying this progress are largely unknown in pigs. Here, we intended to analyze an extensive set of regulators at the single-cell level to define the events involved in the development of the porcine blastocysts. Using a quantitative microfluidics approach in single cells, we detected mRNA levels of 96 genes known to function in early embryonic development and maintenance of stem cell pluripotency simultaneously in 480 individual cells derived from porcine preimplantation embryos...
March 13, 2018: Biology of Reproduction
Jasper Braun, Lukas Nabergall, Rafik Neme, Laura F Landweber, Masahico Saito, Nataša Jonoska
Ciliates have two different types of nuclei per cell, with one acting as a somatic, transcriptionally active nucleus (macronucleus; abbr. MAC) and another serving as a germline nucleus (micronucleus; abbr. MIC). Furthermore, Oxytricha trifallax undergoes extensive genome rearrangements during sexual conjugation and post-zygotic development of daughter cells. These rearrangements are necessary because the precursor MIC loci are often both fragmented and scrambled, with respect to the corresponding MAC loci. Such genome architectures are remarkably tolerant of encrypted MIC loci, because RNA-guided processes during MAC development reorganize the gene fragments in the correct order to resemble the parental MAC sequence...
March 15, 2018: G3: Genes—Genomes—Genetics
Jennifer M Maurer, Charles G Sagerström
BACKGROUND: Signaling cascades, such as the extracellular signal-regulated kinase (ERK) pathway, play vital roles in early vertebrate development. Signals through these pathways are initiated by a growth factor or hormone, are transduced through a kinase cascade, and result in the expression of specific downstream genes that promote cellular proliferation, growth, or differentiation. Tight regulation of these signals is provided by positive or negative modulators at varying levels in the pathway, and is required for proper development and function...
March 15, 2018: BMC Developmental Biology
Erika Toda, Yukinosuke Ohnishi, Takashi Okamoto
Upon double fertilization, one sperm cell fuses with the egg cell to form a zygote with a 1:1 maternal-to-paternal genome ratio (1m:1p), and another sperm cell fuses with the central cell to form a triploid primary endosperm cell with a 2m:1p ratio, resulting in formation of the embryo and the endosperm, respectively. The endosperm is known to be considerably sensitive to the ratio of the parental genome. However, in contrast to endosperm, the effect of an imbalance of the parental genome on zygotic development/embryogenesis has not been well addressed, because it is difficult to reproduce the parental genome-imbalanced situation in zygotes and to monitor the developmental profile of zygotes without external effects from endosperm...
March 10, 2018: Journal of Experimental Botany
C R Sacha, D J Kaser, L V Farland, S Srouji, S A Missmer, C Racowsky
PURPOSE: We examined whether short-term exposure to in vitro maturation (IVM) medium of cumulus-oocyte complexes (COCs) from a stimulated cycle increases the yield of metaphase II (MII) oocytes and usable embryos. METHODS: Retrospective review of two consecutive autologous IVF/ICSI cycles per patient between 2007 and 2015 in which cycle 1 did not result in live birth. Patients with short-term exposure of COCs to IVM medium (3-5 h before standard insemination or ICSI) in cycle 2 (treated) were matched 1:4 on %MI and %MII to patients without use of IVM in cycle 2 (untreated)...
March 14, 2018: Journal of Assisted Reproduction and Genetics
Marie Teixeira, Bénédicte F Py, Christophe Bosc, Daphné Laubreton, Marie-Jo Moutin, Jacqueline Marvel, Frédéric Flamant, Suzy Markossian
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
March 13, 2018: Scientific Reports
E Mangoli, M A Khalili, A R Talebi, S Ghasemi-Esmailabad, A Hosseini
The main goal was to evaluate the correlation between sperm parameters and chromatin quality with embryo kinetics via time-lapse monitoring system (TLM). A total of 40 couples involved in the ICSI program as a result of male infertility. For assessment of sperm chromatin and DNA quality, we used aniline blue, toluidine blue, chromomycin A3, acridine orange and terminal transferase-mediated deoxyuridine triphosphate biotin end labelling assays. All mature oocytes were injected, and the generated zygotes (2PNs) were cultured in TLM...
March 12, 2018: Andrologia
Julian Macoveanu, William Baaré, Kristoffer H Madsen, Lars Vedel Kessing, Hartwig Roman Siebner, Maj Vinberg
Background: Major depression and bipolar disorders aggregates in families and are linked with a wide range of neurobiological abnormalities including cortical gray matter (GM) alterations. Prospective studies of individuals at familial risk may expose the neural mechanisms underlying risk transmission. Methods: We used voxel based morphometry to investigate changes in regional GM brain volume, over a seven-year period, in 37 initially healthy individuals having a mono- or di-zygotic twin diagnosed with major depression or bipolar disorder (high-risk group; mean age 41...
2018: NeuroImage: Clinical
Lei Gao, Keliang Wu, Zhenbo Liu, Xuelong Yao, Shenli Yuan, Wenrong Tao, Lizhi Yi, Guanling Yu, Zhenzhen Hou, Dongdong Fan, Yong Tian, Jianqiao Liu, Zi-Jiang Chen, Jiang Liu
The dynamics of the chromatin regulatory landscape during human early embryogenesis remains unknown. Using DNase I hypersensitive site (DHS) sequencing, we report that the chromatin accessibility landscape is gradually established during human early embryogenesis. Interestingly, the DHSs with OCT4 binding motifs are enriched at the timing of zygotic genome activation (ZGA) in humans, but not in mice. Consistently, OCT4 contributes to ZGA in humans, but not in mice. We further find that lower CpG promoters usually establish DHSs at later stages...
February 28, 2018: Cell
Daigo Inoue, Joachim Wittbrodt, Oliver J Gruss
Centrosomes are the main microtubule organizing centers in animal cells. In particular during embryogenesis, they ensure faithful spindle formation and proper cell divisions. As metazoan centrosomes are eliminated during oogenesis, they have to be reassembled upon fertilization. Most metazoans use the sperm centrioles as templates for new centrosome biogenesis while the egg's cytoplasm re-prepares all components for on-going centrosome duplication in rapidly dividing embryonic cells. We discuss our knowledge and the experimental challenges to analyze zygotic centrosome reformation, which requires genetic experiments to enable scrutinizing respective male and female contributions...
March 9, 2018: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Bastian Bentlage, Karen J Osborn, Dhugal J Lindsay, Russell R Hopcroft, Kevin A Raskoff, Allen G Collins
Loss or stark reduction of the free-swimming medusa or jellyfish stage is common in the cnidarian class Hydrozoa. In the hydrozoan clade Trachylina, however, many species do not possess a sessile polyp or hydroid stage. Trachylines inhabiting freshwater and coastal ecosystems (i.e., Limnomedusae) possess a metagenetic life cycle involving benthic, sessile polyp and free-swimming medusa. In contrast, the paradigm is that open ocean inhabiting, oceanic trachylines (in the orders Narcomedusae and Trachymedusae) develop from zygote to medusa via a free-swimming larva, forgoing the polyp stage...
March 5, 2018: Molecular Phylogenetics and Evolution
Kristin M Whitworth, Raissa Cecil, Joshua A Benne, Bethany K Redel, Lee D Spate, Melissa S Samuel, Randall S Prather, Kevin D Wells
Genetically engineered pigs are often created with a targeting vector that contains a loxP flanked selectable marker like neomycin. The Cre-loxP recombinase system can be used to remove the selectable marker gene from the resulting offspring or cell line. Here is described a new method to remove a loxP flanked neomycin cassette by direct zygote injection of an mRNA encoding Cre recombinase. The optimal concentration of mRNA was determined to be 10 ng/μL when compared to 2 and 100 ng/μL (P < 0.0001)...
March 7, 2018: Transgenic Research
Rebecca Nagel, Frank Kirschbaum, Jacob Engelmann, Volker Hofmann, Felix Pawelzik, Ralph Tiedemann
Effective communication among sympatric species is often instrumental for behavioural isolation, where the failure to successfully discriminate between potential mates could lead to less fit hybrid offspring. Discrimination between con- and heterospecifics tends to occur more often in the sex that invests more in offspring production, i.e. females, but males may also mediate reproductive isolation. In this study, we show that among two Campylomormyrus African weakly electric fish species, males preferentially associate with conspecific females during choice tests using live fish as stimuli, i...
February 2018: Royal Society Open Science
Peter W S Hill, Harry G Leitch, Cristina E Requena, Zhiyi Sun, Rachel Amouroux, Monica Roman-Trufero, Malgorzata Borkowska, Jolyon Terragni, Romualdas Vaisvila, Sarah Linnett, Hakan Bagci, Gopuraja Dharmalingham, Vanja Haberle, Boris Lenhard, Yu Zheng, Sriharsa Pradhan, Petra Hajkova
Gametes are highly specialized cells that can give rise to the next generation through their ability to generate a totipotent zygote. In mice, germ cells are first specified in the developing embryo around embryonic day (E) 6.25 as primordial germ cells (PGCs). Following subsequent migration into the developing gonad, PGCs undergo a wave of extensive epigenetic reprogramming around E10.5-E11.5, including genome-wide loss of 5-methylcytosine. The underlying molecular mechanisms of this process have remained unclear, leading to our inability to recapitulate this step of germline development in vitro...
March 7, 2018: Nature
Alexander Betekhtin, Anna Milewska-Hendel, Joanna Lusinska, Lukasz Chajec, Ewa Kurczynska, Robert Hasterok
The plant cell wall shows a great diversity regarding its chemical composition, which may vary significantly even during different developmental stages. In this study, we analysed the distribution of several cell wall epitopes in embryos of Brachypodium distachyon (Brachypodium). We also described the variations in the nucleus shape and the number of nucleoli that occurred in some embryo cells. The use of transmission electron microscopy, and histological and immunolocalisation techniques permitted the distribution of selected arabinogalactan proteins, extensins, pectins, and hemicelluloses on the embryo surface, internal cell compartments, and in the context of the cell wall ultrastructure to be demonstrated...
March 3, 2018: International Journal of Molecular Sciences
Azusa Inoue, Shogo Matoba, Yi Zhang
This corrects the article DOI: 10.1038/cr.2012.160.
February 2018: Cell Research
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