共查询到20条相似文献,搜索用时 15 毫秒
1.
Measurement of in vivo mutations in human lymphocytes 总被引:15,自引:0,他引:15
2.
DNA-mediated gene transfer (transfection) studies using NIH 3T3 cells as recipients have demonstrated the presence of transforming genes (oncogenes) in diverse human tumours. A large proportion of oncogenes so far detected by DNA transfection are related to the Ha-ras onc gene of Harvey (and BALB) murine sarcoma viruses (MSV), Ki-ras, the oncogene of Kirsten MSV, and a third member of the ras gene family, N-ras. Individual tumours of many different organs have been associated with the activation of members of the ras gene family. We now present the first systematic survey of human urinary tract tumours processed immediately after surgery, as well as normal tissues from the same patients, to detect the presence of such genes. We demonstrate activation of Ha-ras as an oncogene in around 10% of randomly selected urinary tract tumours as well as direct evidence that oncogene activation is the result of a somatic event which is selected for within the tumour cell population. 相似文献
3.
4.
Prevalence of ras gene mutations in human colorectal cancers 总被引:43,自引:0,他引:43
J L Bos E R Fearon S R Hamilton M Verlaan-de Vries J H van Boom A J van der Eb B Vogelstein 《Nature》1987,327(6120):293-297
A combination of DNA hybridization analyses and tissue sectioning techniques demonstrate that ras gene mutations occur in over a third of human colorectal cancers, that most of the mutations are at codon 12 of the c-Ki-ras gene and that the mutations usually precede the development of malignancy. 相似文献
5.
In vivo priming of virus-specific cytotoxic T lymphocytes with synthetic lipopeptide vaccine 总被引:48,自引:0,他引:48
Cytotoxic T lymphocytes (CTL) constitute an essential part of the immune response against viral infections. Such CTL recognize peptides derived from viral proteins together with major histocompatibility complex (MHC) class I molecules on the surface of infected cells, and usually require in vivo priming with infectious virus. Here we report that synthetic viral peptides covalently linked to tripalmitoyl-S-glycerylcysteinyl-seryl-serine (P3CSS) can efficiently prime influenza-virus-specific CTL in vivo. These lipopeptides are able to induce the same high-affinity CTL as does the infectious virus. Our data are not only relevant to vaccine development, but also have a bearing on basic immune processes leading to the transition of virgin T cells to activated effector cells in vivo, and to antigen presentation by MHC class I molecules. 相似文献
6.
7.
Reconstruction of human embryos derived from somatic cells 总被引:1,自引:0,他引:1
GONGFei ZHOUHong TANYueqiu LUGuangxiu LUChangfu LINGe XIEChanqqing 《科学通报(英文版)》2003,48(17):1840-1843
Reconstruction of human nuclear transfer embryos is a necessary step of therapeutic cloning. In this study we injected somatic cell nuclei into M Ⅱ oocytes and activated reconstructed oocytes with calcium ionophore A23187 (CaA) and 6-dimethylaminopurine (6-DMAP). After oocyteactivation and 2PN formation, we removed the female PN.By using this method, we avoided the application of DNA fluorescent stain and ultraviolet light for oocyte enucleation,and over elimination of ooplasm was also mitigated. Some reconstructed embryos developed into the blastocyst stage in vitro. 相似文献
8.
取42例经过病理确认的结直肠癌患者癌组织及癌旁正常组织,抽提基因组DNA,应用单链构象多态性分析(SSCP)、变性高效液相色谱(DHPLC)分析,结合DNA直接测序,在全基因分析humanmutY homologue(MYH)基因胚系突变的同时,探讨其对结直肠癌细胞adenomatous polyposis coli(APC)基因体细胞突变的影响.结果42例患者中检出6例(14.29%)携带MYH基因的胚系突变,其中3例(7.14%)为MYH基因第2外显子单体型突变c.53C>T/c.74G>A(p.Pro18Leu/p.Gly25 Asp),3例(7.14%)为第12外显子的单碱基替换导致的错义突变c.972G>C(p.Gln324His).初步分析显示,这两种突变在正常对照组的检出较低,仅为3/213(1.41%)和0/59(0%).另一方面4/6例携带MYH基因胚系突变患者的癌组织样本中检出5个APC基因体细胞突变.本文结果提示,散发性结直肠癌患者中频繁检出MYH基因的胚系突变,其存在可能导致细胞DNA氧化损伤修复功能减弱,并使机体细胞APC基因发生突变的风险增高,从而可能参与部分结直肠癌的发生. 相似文献
9.
Pennacchio LA Ahituv N Moses AM Prabhakar S Nobrega MA Shoukry M Minovitsky S Dubchak I Holt A Lewis KD Plajzer-Frick I Akiyama J De Val S Afzal V Black BL Couronne O Eisen MB Visel A Rubin EM 《Nature》2006,444(7118):499-502
Identifying the sequences that direct the spatial and temporal expression of genes and defining their function in vivo remains a significant challenge in the annotation of vertebrate genomes. One major obstacle is the lack of experimentally validated training sets. In this study, we made use of extreme evolutionary sequence conservation as a filter to identify putative gene regulatory elements, and characterized the in vivo enhancer activity of a large group of non-coding elements in the human genome that are conserved in human-pufferfish, Takifugu (Fugu) rubripes, or ultraconserved in human-mouse-rat. We tested 167 of these extremely conserved sequences in a transgenic mouse enhancer assay. Here we report that 45% of these sequences functioned reproducibly as tissue-specific enhancers of gene expression at embryonic day 11.5. While directing expression in a broad range of anatomical structures in the embryo, the majority of the 75 enhancers directed expression to various regions of the developing nervous system. We identified sequence signatures enriched in a subset of these elements that targeted forebrain expression, and used these features to rank all approximately 3,100 non-coding elements in the human genome that are conserved between human and Fugu. The testing of the top predictions in transgenic mice resulted in a threefold enrichment for sequences with forebrain enhancer activity. These data dramatically expand the catalogue of human gene enhancers that have been characterized in vivo, and illustrate the utility of such training sets for a variety of biological applications, including decoding the regulatory vocabulary of the human genome. 相似文献
10.
D Baltimore 《Nature》1974,248(447):409-411
11.
12.
Alterations of the hprt gene in human in vivo-derived 6-thioguanine-resistant T lymphocytes 总被引:1,自引:0,他引:1
Investigations into the extent and significance of somatic gene mutations occurring in vivo in humans have been hampered by the lack of a means of unambiguously defining the mutational origin of in vivo-derived variant cells. Several years ago we proposed that 6-thioguanine-resistant T lymphocytes, present at low frequencies in human peripheral blood, might be useful markers of in vivo somatic mutation. We and others have since described methods for the isolation and study of these unusual cells. The thioguanine-resistant T cell stably lack hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity, suggesting that they are somatic equivalents in normal individuals to cells from individuals with the X-chromosomal hprt Lesch-Nyhan germinal mutation. We now report that in vivo-derived thioguanine-resistant T-cell colonies from a single normal individual show a variety of hprt structural alterations, as determined by Southern blot analysis. This finding demonstrates unequivocally that these cells are genetic mutants and validates their use for fundamental and applied mutational studies in humans. 相似文献
13.
In vivo hybridisation of human tumour and normal hamster cells 总被引:5,自引:0,他引:5
14.
15.
16.
17.
Immunological significance of lysosomes with lymphocytes in vivo 总被引:5,自引:0,他引:5
18.
The transporter associated with antigen processing (TAP) is a member of the family of ABC transporters that translocate a large variety of substrates across membranes. TAP transports peptides from the cytosol into the endoplasmic reticulum for binding to MHC class I molecules and for subsequent presentation to the immune system. Here we follow the lateral mobility of TAP in living cells. TAP's mobility increases when it is inactive and decreases when it translocates peptides. Because TAP activity is dependent on substrate, the mobility of TAP is used to monitor the intracellular peptide content in vivo. Comparison of the diffusion rates in peptide-free and peptide-saturated cells indicates that normally about one-third of all TAP molecules actively translocate peptides. However, during an acute influenza infection TAP becomes fully employed owing to the production and degradation of viral proteins. Furthermore, TAP activity depends on continuing protein translation. This implies that MHC class I molecules mainly sample peptides that originate from newly synthesized proteins, to ensure rapid presentation to the immune system. 相似文献
19.
Cloning human lymphocytes in vitro 总被引:2,自引:0,他引:2
20.
R E Hill J Favor B L Hogan C C Ton G F Saunders I M Hanson J Prosser T Jordan N D Hastie V van Heyningen 《Nature》1991,354(6354):522-525