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排序方式: 共有1008条查询结果,搜索用时 15 毫秒
921.
Pengfei Wang Ryan G. Casner Manoj S. Nair Maple Wang Jian Yu Gabriele Cerutti Lihong Liu Peter D. Kwong Yaoxing Huang Lawrence Shapiro David D. Ho 《Cell host & microbe》2021,29(5):747-751.e4
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922.
初论蜘蛛目的种内变异类型 总被引:1,自引:1,他引:0
研究蜘蛛目中的种内变异,初步探讨蜘蛛的外生殖器结构的变异类型,并提出在蜘蛛分类学中树立种群分类概念的重要性。 相似文献
923.
长非编码RNA(long non-coding RNAs, lncRNAs)在肿瘤发生、发展进程中承担重要角色,是近年来的研究热点之一。大量研究表明,浆细胞瘤变异易位基因1(plasmacytoma variant translocation 1, PVT1)可通过多种分子机制参与调控消化系统肿瘤的增殖凋亡、迁移侵袭、细胞自噬、血管生成、多药耐药及肿瘤代谢等过程,从而发挥致癌作用。本文主要就PVT1在消化系统肿瘤中的表达水平变化,及其与临床病理特征和预后的关系,以及PVT1对消化系统肿瘤的致癌作用机制和多药耐药机制等研究进展作一综述。 相似文献
924.
Chloe Rees-Spear Luke Muir Sarah A. Griffith Judith Heaney Yoann Aldon Jonne L. Snitselaar Peter Thomas Carl Graham Jeffrey Seow Nayung Lee Annachiara Rosa Chloe Roustan Catherine F. Houlihan Rogier W. Sanders Ravindra K. Gupta Peter Cherepanov Hans J. Stauss Eleni Nastouli Laura E. McCoy 《Cell reports》2021,34(12):108890
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925.
Xenopus oocytes can synthesise but do not secrete the Z variant of human alpha 1-antitrypsin 总被引:7,自引:0,他引:7
Human liver mRNA was prepared from a patient homozygous for alpha 1-antitrypsin deficiency (PiZZ) and from a normal subject (PiMM). Both liver RNAs were microinjected into Xenopus oocytes and alpha 1-antitrypsin identified by immunoprecipitation. The normal M variant of alpha 1-antitrypsin is synthesised and secreted by Xenopus oocytes, the abnormal Z protein is not secreted and an intracellular form accumulates in the oocytes. In the presence of tunicamycin an unglycosylated form of M alpha 1-antitrypsin appears in the incubation medium but no corresponding unglycosylated version of the Z protein is secreted. 相似文献
926.
The biological control of posttranslational maturation and compartmentalization reactions that operate upon proteins during transport to their final cellular destinations is crucial for normal cellular function. Using the expression of mouse mammary tumor virus (MMTV) glycoproteins as sensitive probes in the viral-infected rat hepatoma cell line M1.54, we have discovered and documented a novel glucocorticoid-regulated trafficking pathway that controls the cell surface localization of MMTV glycoproteins. One complement-selected derivative of M1.54 cells, CR4, failed to compartmentalize cell surface MMTV glycoproteins in the presence of dexamethasone. To test genetically if this glycoprotein trafficking pathway is mediated by cellular or viral gene products, CR4 cells were fused with uninfected Fu5 rat hepatoma cells. Indirect immunofluorescence of CR4 X Fu5 heterokaryons revealed that Fu5 complemented the defect in CR4 only after exposure to 1 microM dexamethasone. The glucocorticoid inhibition of Fu5 proliferation was exploited to recover the receptor-deficient uninfected derivative EDR3 that expressed a 100-fold lower level of [3H]dexamethasone binding activity. Analysis of CR4 X EDR3 cell fusions by indirect immunofluorescence revealed that EDR4 cells complemented CR4 in a dexamethasone-dependent manner, suggesting that EDR3 supplied a functinal trafficking component while CR4 provided a functional glucocorticoid receptor to the heterokaryons. Taken together, our results demonstrate that cellular-encoded glucocorticoid-inducible components mediate the regulated trafficking of cell surface MMTV glycoproteins. 相似文献
927.
Erfan Aref-Eshghi Laila C. Schenkel Hanxin Lin Cindy Skinner Peter Ainsworth Guillaume Paré 《Epigenetics》2017,12(11):923-933
Kabuki syndrome (KS) is caused by mutations in KMT2D, which is a histone methyltransferase involved in methylation of H3K4, a histone marker associated with DNA methylation. Analysis of >450,000 CpGs in 24 KS patients with pathogenic mutations in KMT2D and 216 controls, identified 24 genomic regions, along with 1,504 CpG sites with significant DNA methylation changes including a number of Hox genes and the MYO1F gene. Using the most differentiating and significant probes and regions we developed a “methylation variant pathogenicity (MVP) score,” which enables 100% sensitive and specific identification of individuals with KS, which was confirmed using multiple public and internal patient DNA methylation databases. We also demonstrated the ability of the MVP score to accurately reclassify variants of unknown significance in subjects with apparent clinical features of KS, enabling its potential use in molecular diagnostics. These findings provide novel insights into the molecular etiology of KS and illustrate that DNA methylation patterns can be interpreted as ‘epigenetic echoes’ in certain clinical disorders. 相似文献
928.
Min Zhou Linchang Dai Chengmin Li Liuxin Shi Yan Huang Zhenqian Guo Fei Wu Ping Zhu Zheng Zhou 《The EMBO journal》2021,40(1)
Nucleosomes are dynamic entities with wide‐ranging compositional variations. Human histone variants H2A.B and H2A.Z.2.2 play critical roles in multiple biological processes by forming unstable nucleosomes and open chromatin structures, but how H2A.B and H2A.Z.2.2 confer these dynamic features to nucleosomes remains unclear. Here, we report cryo‐EM structures of nucleosome core particles containing human H2A.B (H2A.B‐NCP) at atomic resolution, identifying large‐scale structural rearrangements in the histone octamer in H2A.B‐NCP. H2A.B‐NCP compacts approximately 103 bp of DNA wrapping around the core histones in approximately 1.2 left‐handed superhelical turns, in sharp contrast to canonical nucleosome encompassing approximately 1.7 turns of DNA. Micrococcal nuclease digestion assay reveals that nineteen H2A.B‐specific residues, including a ROF (“regulating‐octamer‐folding”) sequence of six consecutive residues, are responsible for loosening of H2A.B‐NCPs. Unlike H2A.B‐NCP, the H2A.Z.2.2‐containing nucleosome (Z.2.2‐NCP) adopts a less‐extended structure and compacts around 125 bp of DNA. Further investigation uncovers a crucial role for the H2A.Z.2.2‐specific ROF in both H2A.Z.2.2‐NCP opening and SWR1‐dependent histone replacement. Taken together, these first high‐resolution structure of unstable nucleosomes induced by histone H2A variants elucidate specific functions of H2A.B and H2A.Z.2.2 in enhancing chromatin dynamics. 相似文献
929.
Anders Johannisson Birgitta Eriksson Herman Amnéus Gösta Zetterberg 《Cell biology and toxicology》1992,8(4):233-253
Attempts have been made to use the hypoxanthine-guanine-phospho-ribosyl-transferase-assay as a method for automated screening of agent-induced phenotypic variants of human peripheral lymphocytes reflecting 6-thioguanine resistance and assumed to indicate genotoxic action. Different protocols of the hypoxanthine-guanine-phospho-ribosyl-transferase-system were used in this study in order to investigate whether the system can be a candidate for a short-term test for a rapid and reliable identification of biological systems exposed to agents. The current protocols were based on: 1) fluoresceinated monoclonal antibodies against bromodeoxyuridine-DNA for labelling of 6-thioguanine-resistant human lymphocytes and direct flow-cytometric enumeration of bromodeoxyuridine-positive events and: 2) indirect flow-cytometric enrichment of 6-thioguanine-resistant cells labelled with 3H-thymidine followed by autoradiographic enumeration of positive events. Both the direct and the indirect enumeration method yielded similar results down to the range 10–4 with respect to frequency of variants. For the less time-consuming direct enumeration method the resolution was limited due to non-specific binding of the antibody and false positives. It was, nevertheless, sufficient to score variants induced in vitro with the mutagens EMS, MMC and TT in the same range as e.g. that of cancer patients during and after chemotherapy or radiotherapy, or that of psoriasis patients during and after PUVA (8-methoxypsoralen and long range UV light)-therapy. We conclude that the direct enumeration protocol can be used for a rapid screening of so called outliers, but a more sensitive test, such as the more time-consuming enrichment protocol based on autoradiography, must be used in order to score variants in the range 10–5–10–6
Abbreviations
3H-TdR
Tritiated thymidine
- BrdU
5-2-bromodeoxyuridine
- DNA
Deoxyribonucleic acid
- EMS
Ethyl-methanesulphonate
- FBS
Fetal bovine serum
- FITC
Fluorescein Isothiocyanate
- G0
Cell cycle stage
- G1
Cell cycle stage
- G2
Cell cycle stage
- HPRT
Hypoxanthine Guanine Phospho Ribosyl Transferase
- LI
Labelling index
- MMC
Mitomycin C
- PBL
Peripheral blood lymphocytes
- PBS
Phosphate buffered saline
- PHA
Phytohemagglutinin
- PI
Propidium iodide
- PUVA
8-Methoxypsoralen and long range UV-light therapy
- RNA
Ribonucleic acid
- RPMI
RPMI-1640 culturing medium
- Se
Early S-stage in the cell-cycle
- Sl
Late S-stage in the cell-cycle
- SCE
Sister chromatid exchange
- TG
6-Thioguanine
- TT
Thiotepa
- UV
Ultraviolet light
- Vf
Variant frequency 相似文献
930.
A comparison is made of single components of the homozygous variants A and D2 of bovine serum transferrin by tryptic, chymotryptic and cyanogen bromide digestion. It is concluded that there are three substitutions A:D2 - Glu:Asp, Lys: Arg and Asp:Gly. In the light of the recent work of Brocket al. (1980) it is concluded that all three substitutions occur in the C-terminal sequence of the chain. By homology with the sequence of human serum transferrin (MacGillivray et al., 1982) the Lys:Arg and Asp:Gly substitutions probably occur at residues 527 and 446, respectively, from the N -terminus. The Asp:Gly substitution is considered more likely than our earlier conclusion (Maeda, McKenzie & Shaw, 1977) that there is a deletion in the chain of D2 (A:D2 , Asp: —). The location of the Glu:Asp substitution is not known. 相似文献