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1. chinaXiv:201605.01481 [pdf]

LSY-2 is essential for maintaining the germ-soma distinction in C-elegans

Lin, Long; Lin, Long; Yan, Libo; Zhao, Yu; Lin, Long; Li, Yuping; Zhang, Gangming; Zhang, Hong
Subjects: Biology >> Biophysics >> Cell Biology

The mechanisms that specify and maintain the characteristics of germ cells during animal development are poorly understood. In this study, we demonstrated that loss of function of the zinc-finger gene lsy-2 results in various somatic cells adopting germ cells characteristics, including expression of germline-specific P granules, enhanced RNAi activity and transgene silencing. The soma to germ transformation in lsy-2 mutants requires the activities of multiple chromatin remodeling complexes, including the MES-4 complex and the ISW-1 complex. The distinct germline-specific features in somatic cells and the gene expression profile indicate that LSY-2 acts in the Mec complex in this process. Our study demonstrated that lsy-2 functions in the maintenance of the soma-germ distinction.

submitted time 2016-05-12 Hits2555Downloads1450 Comment 0

2. chinaXiv:201605.01456 [pdf]

Characterization of quinolone resistance in Salmonella enterica serovar Indiana from chickens in China

Lu, Yan; Liu, Yuqi; Zhou, Xuping; Hou, Xiaolin; Zhao, Hongyu; Wang, Jinyuan; Liu, Tiantian; Beier, Ross C.
Subjects: Biology >> Biophysics

The aim of this study was to characterize the quinolone resistance of Salmonella enterica serovar Indiana isolated from chickens in China. A total of 293 Salmonella strains were isolated from chicken farms and slaughterhouses in Shandong province of China, and 130 (44.4%) were characterized as Salmonella enterica Indiana (chicken farms, n = 52 strains; slaughter houses, n = 78 strains). All isolate serotypes were tested with the Kauffmann-White classification system and examined for susceptibility to the quinolones: nalidixic acid, enrofloxacin, norfloxacin, and ciprofloxacin. The resistance of the Salmonella Indiana strains to nalidixic acid, enrofloxacin, norfloxacin, and ciprofloxacin were 100, 73.1, 71.2, and 82.7%, and 100, 59.0, 79.5, and 80.2%, respectively. Selected quinolone resistant strains were evaluated for mutations in genes (gyrA, gyrB, parC, and marA) by DNA sequencing. The gyrA mutation was found in all isolates, the parC mutation was only found in some isolates, and the gyrB and marA mutations were not observed. Quinolone resistance was evaluated in the representative isolates by screening for the quinolone resistance determinants, qnrA, qnrB, qnrS, qepA, and aac (6')-Ib-cr using PCR technology. The quinolone resistance determinants in Salmonella, qnrA, qnrB, qnrS, and qepA were negative by PCR, but aac(6')-Ib-cr had high detection rates of 90.4 and 96.2% in chicken farms and slaughterhouses, respectively. Salmonella Indiana containing the gyrA mutation was prevalent in farms and slaughterhouses and possessed a high frequency of the quinolone resistance determinant aac(6')-Ib-cr. These bacteria may have originated from the same source.

submitted time 2016-05-12 Hits1291Downloads792 Comment 0

3. chinaXiv:201605.01378 [pdf]

Interactome analysis identifies a new paralogue of XRCC4 in non-homologous end joining DNA repair pathway

Xing, Mengtan; Huo, Wei; Ning, Shaokai; Yan, Zhenxin; Li, Wen; Wang, Qingsong; Hou, Mei; Dong, Chunxia; Guo, Rong; Gao, Ge; Ji, Jianguo; Xu, Dongyi; Yang, Mingrui; Feng, Feng; Liang, Huanhuan; Yang, Mingrui; Wei, Leizhen; Lan, Li; Jiang, Wenxia; Zha, Shan
Subjects: Biology >> Biophysics

Non-homologous end joining (NHEJ) is a major pathway to repair DNA double-strand breaks (DSBs), which can display different types of broken ends. However, it is unclear how NHEJ factors organize to repair diverse types of DNA breaks. Here, through systematic analysis of the human NHEJ factor interactome, we identify PAXX as a direct interactor of Ku. The crystal structure of PAXX is similar to those of XRCC4 and XLF. Importantly, PAXX-deficient cells are sensitive to DSB-causing agents. Moreover, epistasis analysis demonstrates that PAXX functions together with XLF in response to ionizing radiation-induced complex DSBs, whereas they function redundantly in response to Topo2 inhibitor-induced simple DSBs. Consistently, PAXX and XLF coordinately promote the ligation of complex but not simple DNA ends in vitro. Altogether, our data identify PAXX as a new NHEJ factor and provide insight regarding the organization of NHEJ factors responding to diverse types of DSB ends.

submitted time 2016-05-12 Hits1166Downloads711 Comment 0

4. chinaXiv:201605.00715 [pdf]

Auxilin facilitates membrane traffic in the early secretory pathway

Ding, Jingzhen; Chen, Shuliang; Ferro-Novick, Susan; Segarra, Veronica A.; Lemmon, Sandra K.; Cai, Huaqing;
Subjects: Biology >> Biophysics >> Cell Biology

Coat protein complexes contain an inner shell that sorts cargo and an outer shell that helps deform the membrane to give the vesicle its shape. There are three major types of coated vesicles in the cell: COPII, COPI, and clathrin. The COPII coat complex facilitates vesicle budding from the endoplasmic reticulum (ER), while the COPI coat complex performs an analogous function in the Golgi. Clathrin-coated vesicles mediate traffic from the cell surface and between the trans-Golgi and endosome. While the assembly and structure of these coat complexes has been extensively studied, the disassembly of COPII and COPI coats from membranes is less well understood. We describe a proteomic and genetic approach that connects the J-domain chaperone auxilin, which uncoats clathrin-coated vesicles, to COPII and COPI coat complexes. Consistent with a functional role for auxilin in the early secretory pathway, auxilin binds to COPII and COPI coat subunits. Furthermore, ER-Golgi and intra-Golgi traffic is delayed at 15 degrees C in swa2 Delta mutant cells, which lack auxilin. In the case of COPII vesicles, we link this delay to a defect in vesicle fusion. We propose that auxilin acts as a chaperone and/or uncoating factor for transport vesicles that act in the early secretory pathway.

submitted time 2016-05-05 Hits1293Downloads652 Comment 0

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