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Conditional knock-out

Michael G Moldavan, Patricia J Sollars, Michael R Lasarev, Charles N Allen, Gary E Pickard
Intrinsically photosensitive retinal ganglion cells (ipRGCs) innervate the hypothalamic suprachiasmatic nucleus (SCN), a circadian oscillator that functions as a biological clock. ipRGCs use vesicular glutamate transporter 2 (vGlut2) to package glutamate into synaptic vesicles and light-evoked resetting of the SCN circadian clock is widely attributed to ipRGC glutamatergic neurotransmission. Pituitary adenylate cyclase-activating polypeptide (PACAP) is also packaged into vesicles in ipRGCs and PACAP may be coreleased with glutamate in the SCN...
May 2018: ENeuro
Qiang Fei, Aaron W Puri, Holly Smith, Nancy Dowe, Philip T Pienkos
Background: Due to the success of shale gas development in the US, the production cost of natural gas has been reduced significantly, which in turn has made methane (CH4 ), the major component of natural gas, a potential alternative substrate for bioconversion processes compared with other high-price raw material sources or edible feedstocks. Therefore, exploring effective ways to use CH4 for the production of biofuels is attractive. Biological fixation of CH4 by methanotrophic bacteria capable of using CH4 as their sole carbon and energy source has obtained great attention for biofuel production from this resource...
2018: Biotechnology for Biofuels
Olga Chodelkova, Jan Masek, Vladimir Korinek, Zbynek Kozmik, Ondrej Machon
Generation of neurons in the embryonic neocortex is a balanced process of proliferation and differentiation of neuronal progenitor cells. Canonical Wnt signalling is crucial for expansion of radial glial cells in the ventricular zone and for differentiation of intermediate progenitors in the subventricular zone. We detected abundant expression of two transcrtiption factors mediating canonical Wnt signalling, Tcf7L1 and Tcf7L2, in the ventricular zone of the embryonic neocortex. Conditional knock-out analysis showed that Tcf7L2, but not Tcf7L1, is the principal Wnt mediator important for maintenance of progenitor cell identity in the ventricular zone...
May 11, 2018: Neural Development
M Hofer, Z Hoferová, J Remšík, M Nováková, J Procházková, R Fedr, J Kohoutek, L Dušek, A Hampl, K Souček
Several members of the TGF-beta family are known to effectively regulate the fate of hematopoietic progenitor cells in a complex and context-dependent manner. Growth differentiation factor-15 (GDF15) is a divergent member of the TGF-beta family. This stress-induced cytokine has been proposed to possess immunomodulatory functions and its high expression is often associated with progression of a variety of pathological conditions. GDF15 is also induced by chemotherapy and irradiation. Very few fundamental studies have been published regarding the effect of GDF15 in hematopoiesis...
May 10, 2018: Physiological Research
Mengxia Li, Xiao Yang, Xianfeng Lu, Nan Dai, Shiheng Zhang, Yi Cheng, Lei Zhang, Yuxin Yang, Yie Liu, Zhenzhou Yang, Dong Wang, David M Wilson
Base excision repair (BER) handles many forms of endogenous DNA damage, and apurinic/apyrimidinic endonuclease 1 (APE1) is central to this process. Deletion of both alleles of APE1 (a.k.a. Apex1) in mice leads to embryonic lethality, and deficiency in cells can promote cell death. Unlike most other BER proteins, APE1 expression is inversely correlated with cellular senescence in primary human fibroblasts. Depletion of APE1 via shRNA induced senescence in normal human BJ fibroblasts, a phenotype that was not seen in counterpart cells expressing telomerase...
May 10, 2018: Nucleic Acids Research
Sabrina Zechel, Diana Fernandez-Suarez, Carlos F Ibáñez
GFRα1, a receptor for glial cell line-derived neurotrophic factor (GDNF), is critical for the development of the main olfactory system. The olfactory bulb (OB) of Gfra1 knock-out mice shows significant reductions in the number of olfactory sensory neurons, mitral and tufted cells, as well as all major classes of OB GABAergic interneurons. However, the latter do not express significant levels of GFRα1, leaving the mechanism of action of GFRα1 in OB interneuron development unexplained. Here we report that GFRα1 is highly expressed in the precursor cells that give rise to all major classes of OB interneurons, but is downregulated as these neurons mature...
May 1, 2018: Biology Open
Nobuhiko Tachibana, Yacine Touahri, Rajiv Dixit, Luke Ajay David, Lata Adnani, Robert Cantrup, Tooka Aavani, Rachel O Wong, Cairine Logan, Kyle C Kurek, Carol Schuurmans
PTEN Hamartoma Tumor Syndrome (PHTS) is a heterogeneous group of rare, autosomal dominant disorders associated with PTEN germline mutations. PHTS patients routinely develop hamartomas, which are benign tissue overgrowths comprised of disorganized 'normal' cells. Efforts to generate PHTS animal models have been largely unsuccessful due to the early lethality of homozygous germline mutations in Pten , together with the lack of hamartoma formation in most conditional mutants generated to date. We report herein a novel PHTS mouse model that reproducibly forms hamartoma-like lesions in the central retina by postnatal day 21...
April 24, 2018: Disease Models & Mechanisms
Alyssa N King, Samiksha Borkar, David J Samuels, Zachary Batz, Logan Bulock, Marat R Sadykov, Kenneth W Bayles, Shaun R Brinsmade
In Staphylococcus aureus , the global transcriptional regulator CodY modulates the expression of hundreds of genes in response to the availability of GTP and the branched-chain amino acids isoleucine, leucine, and valine (ILV). CodY DNA-binding activity is high when GTP and ILV are abundant. When GTP and ILV are limited, CodY's affinity for DNA drops, altering expression of CodY regulated targets. In this work, we investigated the impact of guanine nucleotides on S. aureus physiology and CodY activity by constructing a guaA null mutant (Δ guaA )...
April 30, 2018: Journal of Bacteriology
Diego Marin, Alexandra L Nguyen, Richard T Scott, Karen Schindler
Embryonic aneuploidy is the major genetic cause of infertility in humans. Most of these events originate during female meiosis, and albeit positively correlated with maternal age, age alone is not always predictive of the risk of generating an aneuploid embryo. Therefore, gene variants might account for incorrect chromosome segregation during oogenesis. Given that access to human oocytes is limited for research purposes, a series of assays were developed to study human gene function during meiosis I using mouse oocytes...
April 10, 2018: Journal of Visualized Experiments: JoVE
Charis Achilleos, Stella Michael, Katerina Strati
High-risk human papillomaviruses (HPVs) have been shown in vitro to impinge on telomere homeostasis in a number of ways. However, the in vivo interaction of viruses with the telomere homeostasis apparatus has not been previously explored. Since E6 and E7 are the main viral oncogenes and key for viral replication, we have explored here the short-term phenotypes of the genes in the context of defective telomere homeostasis. We examined the short-term phenotypes of E6 and E7 in a context where the Terc component of the telomerase holoenzyme was knocked out...
2018: PloS One
Ilaria Barchetta, Flavia Agata Cimini, Danila Capoccia, Laura Bertoccini, Valentina Ceccarelli, Caterina Chiappetta, Frida Leonetti, Claudio Di Cristofano, Gianfranco Silecchia, Marju Orho-Melander, Olle Melander, Maria Gisella Cavallo
Neurotensin (NT) is a 13-amino acid peptide localized in the neuroendocrine cells of the small intestine, which promotes fat absorption and fatty acids translocation in response to lipid ingestion. NT-knock-out mice fed with a high-fat diet are protected from obesity, fatty liver, and the development of insulin-resistance. In humans, higher plasma levels of pro-NT, which is the stable circulating precursor of NT, predict obesity, type 2 diabetes (T2D), and cardiovascular disease. In obesity, the presence of visceral adipose tissue (VAT) inflammation leads to unfavorable metabolic outcomes and is associated with the development of T2D and non-alcoholic fatty liver disease (NAFLD)...
April 23, 2018: Nutrients
Ahmed Bahieldin, Ahmed Atef, Sherif Edris, Nour O Gadalla, Ahmed M Ramadan, Sabah M Hassan, Sanaa G Al Attas, Magdy A Al-Kordy, Abdulrahman S M Al-Hajar, Jamal S M Sabir, Mahmoud E Nasr, Gamal H Osman, Fotouh M El-Domyati
Transcriptomic analysis was conducted in leaves of Arabidopsis T-DNA insertion ERF109-knocked out (KO) mutant or plants overexpressing (OE) the gene to detect its role in driving expression of programmed cell death- (PCD-) or growth-related genes under high salt (200 mM NaCl) stress. The analysis yielded ~22-24 million reads, of which 90% mapped to the Arabidopsis reference nuclear genome. Hierarchical cluster analysis of gene expression and principal component analysis (PCA) successfully separated transcriptomes of the two stress time points...
April 23, 2018: Scientific Reports
Hongchang Li, Pengfei Zhang, Qiuyue Zhang, Chaonan Li, Weiguo Zou, Zhijie Chang, Chun-Ping Cui, Lingqiang Zhang
The tumor suppressor phosphatase and tensin homolog (PTEN) plays a central role in regulating phosphatidylinositol-3-kinase (PI3K) signaling, and its gene is very frequently mutated in various human cancers. Numerous studies have revealed that PTEN levels are tightly regulated by both transcriptional and post-translational modifications, with especially ubiquitylation significantly regulating PTEN protein levels. Although several ubiquitin ligases have been reported to mediate PTEN ubiquitylation in vitro , the ubiquitin ligase that promotes PTEN degradation in vivo has not been reported...
April 23, 2018: Journal of Biological Chemistry
Prosenjit Pyne, Masrure Alam, Moidu Jameela Rameez, Subhrangshu Mandal, Abhijit Sar, Nibendu Mondal, Utsab Debnath, Boby Mathew, Anup Kumar Misra, Amit Kumar Mandal, Wriddhiman Ghosh
The SoxXAYZB(CD)2 -mediated pathway of bacterial sulfur-chemolithotrophy explains the oxidation of thiosulfate, sulfide, sulfur and sulfite, but not tetrathionate. Advenella kashmirensis, which oxidizes tetrathionate to sulfate, besides forming it as an intermediate during thiosulfate-oxidation, possesses a soxCDYZAXOB operon. Knock-out-mutations proved that only SoxBCD is involved in A. kashmirensis tetrathionate-oxidation, whereas thiosulfate-to-tetrathionate-conversion is Sox-independent. Expression of two glutathione-metabolism-related proteins increased under chemolithotrophic conditions, as compared to the chemoorganotrophic one...
April 18, 2018: Molecular Microbiology
Yunlong Xia, Fuyang Zhang, Shihao Zhao, Yueyang Li, Xiyao Chen, Erhe Gao, Xinyue Xu, Zhenyu Xiong, Xiaomeng Zhang, Jinglong Zhang, Huishou Zhao, Wei Wang, Helin Wang, Yanjie Guo, Yi Liu, Congye Li, Shan Wang, Ling Zhang, Wenjun Yan, Ling Tao
Aims: The farnesoid X receptor (FXR) is a member of the metabolic nuclear receptor superfamily that plays a critical regulatory role in cardiovascular physiology/pathology. However, the role of systemic FXR activation in the chronic phase in myocardial infarction (MI)-induced cardiac remodeling and dysfunction remains unclear. In this study, we aimed to elucidate the role of long-term FXR activation on post-MI cardiac remodeling and dysfunction. Methods and Results: Mice underwent either MI surgery or sham operation...
April 14, 2018: Cardiovascular Research
Lian Jin, Yan Deng, Nongyue He, Lijun Wang, Mengling Weng
CCR5 acts as one of the key coreceptors for human immunodeficiency virus infection, which leads to acquired immune deficiency syndrome. CCR5 gene knockout comes up as an alternative method for treatment of the disease. Transcription activator-like effector nuclease is a powerful gene editing tool characterized by the ease of design, high rates of cleavage activity, and the accessibility of all ranges of transcription activator-like effector nucleases. In this study, transcription activator-like effector nuclease plasmids specifically targeting to knock out CCR5 gene were designed, constructed and then transfected to Hela and HEK293T cell lines with the assistance of the well-established gene delivery carrier polyethylenimine...
March 1, 2018: Journal of Biomedical Nanotechnology
Yue Hu, Jian Jiao, Li Xue Liu, Yan Wei Sun, Wenfeng Chen, Xinhua Sui, Wenxin Chen, Chang Fu Tian
Phosphate homeostasis is tightly modulated in all organisms including bacteria, which harbor both high- and low-affinity transporters acting under conditions of fluctuating phosphate levels. It was thought that nitrogen-fixing rhizobia, named as bacteroids, inhabiting root nodules of legumes are not phosphate limited. Here we show that the high-affinity phosphate transporter PstSCAB other than the low-affinity phosphate transporter Pit is essential for effective nitrogen fixation of Sinorhizobium fredii in soybean nodules...
April 17, 2018: Molecular Plant-microbe Interactions: MPMI
Sydney Aten, Katelin F Hansen, Kaitlin Snider, Kelin Wheaton, Anisha Kalidindi, Ashley Garcia, Diego Alzate-Correa, Kari R Hoyt, Karl Obrietan
The microRNA miR-132 serves as a key regulator of a wide range of plasticity-associated processes in the central nervous system. Interestingly, miR-132 expression has also been shown to be under the control of the circadian timing system. This finding, coupled with work showing that miR-132 is expressed in the hippocampus, where it influences neuronal morphology and memory, led us to test the idea that daily rhythms in miR-132 within the forebrain modulate cognition as a function of circadian time. Here, we show that hippocampal miR-132 expression is gated by the time-of-day, with peak levels occurring during the circadian night...
May 2018: Learning & Memory
Alan Y Hsu, Theodore Gurol, Tiago J P Sobreira, Sheng Zhang, Natalie Moore, Chufan Cai, Zhong-Yin Zhang, Qing Deng
Endotoxemia is a condition in which endotoxins enter the blood stream and cause systemic and sometimes lethal inflammation. Zebra fish provides a genetically tractable model organism for studying innate immunity, with additional advantages in live imaging and drug discovery. However, a bona fide endotoxemia model has not been established in zebra fish. Here, we have developed an acute endotoxemia model in zebra fish by injecting a single dose of LPS directly into the circulation. Hallmarks of human acute endotoxemia, including systemic inflammation, extensive tissue damage, circulation blockade, immune cell mobilization, and emergency hematopoiesis, were recapitulated in this model...
2018: Frontiers in Immunology
Vera Novy, Bernd Brunner, Bernd Nidetzky
BACKGROUND: Saccharomyces cerevisiae, engineered for L-lactic acid production from glucose and xylose, is a promising production host for lignocellulose-to-lactic acid processes. However, the two principal engineering strategies-pyruvate-to-lactic acid conversion with and without disruption of the competing pyruvate-to-ethanol pathway-have not yet resulted in strains that combine high lactic acid yields (YLA ) and productivities (QLA ) on both sugar substrates. Limitations seemingly arise from a dependency on the carbon source and the aeration conditions, but the underlying effects are poorly understood...
April 11, 2018: Microbial Cell Factories
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