共查询到20条相似文献，搜索用时 31 毫秒
1.
New method for detecting cellular transforming genes 总被引：24，自引：0，他引：24
D G Blair C S Cooper M K Oskarsson L A Eader G F Vande Woude 《Science (New York, N.Y.)》1982,218(4577):1122-1125
Tumor induction in athymic nude mice can be used to detect dominant transforming genes in cellular DNA. Mouse NIH 3T3 cells freshly transfected with either cloned Moloney sarcoma proviral DNA or cellular DNA's derived from virally transformed cells induced tumors when injected into athymic nu/nu mice. Tumors were also induced by cells transfected with DNA from two tumor-derived and one chemically transformed human cell lines. The mouse tumors induced by human cell line DNA's contained human DNA sequences, and DNA derived from these tumors was capable of inducing both tumors and foci on subsequent transfection. Tumor induction in nude mice represents a useful new method for the detection and selection of cells transformed by cellular oncogenes. 相似文献
2.
Frequent activation of c-kis as a transforming gene in fibrosarcomas induced by methylcholanthrene 总被引：20，自引：0，他引：20
The DNA's from two of four methylcholanthrene-induced mouse fibrosarcomas contained transforming genes that were identical in their pattern of restriction endonuclease resistance to inactivation of biologic activity. This transforming gene was identified as the activated homolog of the Kirsten murine sarcoma virus onc gene, v-kis. The finding that a defined carcinogen reproducibly leads to activation of kis as a transforming gene should be of value in elucidating the role of oncogenes in the neoplastic process. 相似文献
3.
4.
Mammalian and yeast ras gene products: biological function in their heterologous systems 总被引：60，自引：0，他引：60
D DeFeo-Jones K Tatchell L C Robinson I S Sigal W C Vass D R Lowy E M Scolnick 《Science (New York, N.Y.)》1985,228(4696):179-184
Activated versions of ras genes have been found in various types of malignant tumors. The normal versions of these genes are found in organisms as diverse as mammals and yeasts. Yeast cells that lack their functional ras genes, RASSC-1 and RASSC-2, are ordinarily nonviable. They have now been shown to remain viable if they carry a mammalian rasH gene. In addition, yeast-mammalian hybrid genes and a deletion mutant yeast RASSC-1 gene were shown to induce morphologic transformation of mouse NIH 3T3 cells when the genes had a point mutation analogous to one that increases the transforming activity of mammalian ras genes. The results establish the functional relevance of the yeast system to the genetics and biochemistry of cellular transformation induced by mammalian ras genes. 相似文献
5.
The mouse homolog (c-sis) of the transforming gene of the simian sarcoma virus was mapped to chromosome 15 by the Southern blot analysis of DNA's from hamster-mouse somatic cell hybrids. Alterations in c-sis expression may thus play a role in the various murine neoplastic diseases characterized by rearrangements or duplications of chromosome 15. 相似文献
6.
The x gene is essential for HTLV replication 总被引：44，自引：0，他引：44
I S Chen D J Slamon J D Rosenblatt N P Shah S G Quan W Wachsman 《Science (New York, N.Y.)》1985,229(4708):54-58
7.
DNA-mediated gene transfer (transfection) is used to introduce specific genes into vertebrate cells. Events soon after transfection were quantitatively analyzed by determining the infectivity of the DNA from an avian retrovirus and of mixtures of subgenomic fragments of this DNA. The limiting step of transfection with two DNA molecules is the uptake by a single cell of both DNA's in a biologically active state. Transfected cells mediate ligation and recombination of physically unlinked DNA's at nearly 100 percent efficiency. 相似文献
8.
Cellular transformation by human papillomavirus DNA in vitro 总被引：15，自引：0，他引：15
S L Watts W C Phelps R S Ostrow K R Zachow A J Faras 《Science (New York, N.Y.)》1984,225(4662):634-636
Molecularly cloned DNA's of human papillomaviruses HPV-5 and HPV-l induced morphological transformation of mouse C127 cells in culture. Single-cell clones of cells transformed by papillomavirus contained multiple persistent episomal copies of the transfected DNA species and were analyzed for growth characteristics indicating malignant potential. 相似文献
9.
Activation of the cellular proto-oncogene product p21Ras by addition of a myristylation signal 总被引：30，自引：0，他引：30
J E Buss P A Solski J P Schaeffer M J MacDonald C J Der 《Science (New York, N.Y.)》1989,243(4898):1600-1603
The 21-kD proteins encoded by ras oncogenes (p21Ras) are modified covalently by a palmitate attached to a cysteine residue near the carboxyl terminus. Changing cysteine at position 186 to serine in oncogenic forms produces a nonpalmitylated protein that fails to associate with membranes and does not transform NIH 3T3 cells. Nonpalmitylated p21Ras derivatives were constructed that contained myristic acid at their amino termini to determine if a different form of lipid modification could restore either membrane association or transforming activity. An activated p21Ras, altered in this way, exhibited both efficient membrane association and full transforming activity. Surprisingly, myristylated forms of normal cellular Ras were also transforming. This demonstrates that Ras must bind to membranes in order to transmit a signal for transformation, but that either myristate or palmitate can perform this role. However, the normal function of cellular Ras is diverted to transformation by myristate and therefore must be regulated ordinarily by some unique property of palmitate that myristate does not mimic. Myristylation thus represents a novel mechanism by which Ras can become transforming. 相似文献
10.
Molecular genetics of inherited variation in human color vision 总被引：58，自引：0，他引：58
J Nathans T P Piantanida R L Eddy T B Shows D S Hogness 《Science (New York, N.Y.)》1986,232(4747):203-210
The hypothesis that red-green "color blindness" is caused by alterations in the genes encoding red and green visual pigments has been tested and shown to be correct. Genomic DNA's from 25 males with various red-green color vision deficiencies were analyzed by Southern blot hybridization with the cloned red and green pigment genes as probes. The observed genotypes appear to result from unequal recombination or gene conversion (or both). Together with chromosome mapping experiments, these data identify each of the cloned human visual pigment genes. 相似文献
11.
Genetic reconstitution of functional acetylcholine receptor channels in mouse fibroblasts 总被引：12，自引：0，他引：12
T Claudio W N Green D S Hartman D Hayden H L Paulson F J Sigworth S M Sine A Swedlund 《Science (New York, N.Y.)》1987,238(4834):1688-1694
Foreign genes can be stably integrated into the genome of a cell by means of DNA-mediated gene transfer techniques, and large quantities of homogenous cells that continuously express these gene products can then be isolated. Such an expression system can be used to study the functional consequences of introducing specific mutations into genes and to study the expressed protein in the absence of cellular components with which it is normally in contact. All four Torpedo acetylcholine receptor (AChR) subunit complementary DNA's were introduced into the genome of a mouse fibroblast cell by DNA-mediated gene transfer. A clonal cell line that stably produced high concentrations of correctly assembled cell surface AChR's and formed proper ligand-gated ion channels was isolated. With this new expression system, recombinant DNA, biochemical, pharmacological, and electrophysiological techniques were combined to study Torpedo AChR's in a single intact system. The physiological and pharmacological profiles of Torpedo AChR's expressed in mouse fibroblast cells differ in some details from those described earlier, and may provide a more accurate reflection of the properties of this receptor in its natural environment. 相似文献
12.
Chromosomal localization of the human homolog (c-sis) of the simian sarcoma virus onc gene 总被引：34，自引：0，他引：34
Nonrandom chromosome rearrangements of chromosome 22 have been identified in different human malignancies. As a result of Southern blot hybridization of a c-sis probe to DNA's from mouse-human somatic cell hybrids, the human homolog (c-sis) of the transforming gene of simian sarcoma virus was assigned to chromosome 22. Hybrids between thymidine kinase-deficient mouse cells and human fibroblasts carrying a translocation of the region q11-qter of chromosome 22 to chromosome 17 were also analyzed. These studies demonstrate that the human c-sis gene is on region 22q11 greater than qter. 相似文献
13.
植物抗病及抗虫基因工程的研究进展 总被引：4，自引：0，他引：4
建立在分子生物学技术基础上的植物基因工程操作,为抗病虫害作物品种的培育提供了一条崭新而有效的途径。它主要通过将外源抗性相关基因导入受体植物以提高植物的抗性。目前,在抗病虫害基因的分离、转化等方面均取得了令人瞩目的进展。本文将就抗病及抗虫基因工程两方面对目前的研究现状作一综述。 相似文献
14.
A T Garber C Winkler T Shinohara C R King G Inana J Piatigorsky R J Gold 《Science (New York, N.Y.)》1985,227(4682):74-77
The eye lens of the Fraser mouse contains a dominantly inherited cataract with reduced amounts of seven distinct but homologous gamma crystallins encoded by a family of gamma-crystallin genes. The results of experiments with cultured lenses, cell-free RNA translation, and Northern blot hybridization indicated a specific loss of the family of gamma-crystallin messenger RNA's in the Fraser mouse lens. Southern blot hybridization of genomic DNA's from normal and Fraser mice showed no differences in gamma-crystallin coding sequences. 相似文献
15.
Stable amplified DNA in drug-resistant Leishmania exists as extrachromosomal circles 总被引：18，自引：0，他引：18
The relative stability of amplified DNA in drug-resistant Leishmania major was previously reported to be dependent on location, that is, unstable amplified DNA was extrachromosomal and stable amplified DNA was chromosomal. Leishmanial chromosomes have now been directly examined by means of orthogonal-field-alternation gel electrophoresis (OFAGE). The amplified DNA's in three resistant cell lines displayed unusual migration and were clearly extrachromosomal, regardless of whether the amplified DNA's were stable or unstable. Thus, contrary to conclusions from earlier studies of drug resistance in cultured animal cells, stable amplified DNA in Leishmania can be extrachromosomal. In addition, these amplified DNA's were shown to be circular on the basis of their resistance to exonuclease III digestion and their behavior on OFAGE. Their mobility was also greatly changed after treatment with topoisomerase II, suggesting that the amplified DNA's were either supercoiled or concatenated circles. 相似文献
16.
Activated proto-onc genes: sufficient or necessary for cancer? 总被引：20，自引：0，他引：20
P H Duesberg 《Science (New York, N.Y.)》1985,228(4700):669-677
17.
The E5 transforming gene of bovine papillomavirus encodes a small, hydrophobic polypeptide 总被引：47，自引：0，他引：47
Bovine papillomavirus (BPV-1) contains two independent transforming genes that have been mapped to the E5 and E6 open reading frames (ORF's). The E5 transforming protein was identified by means of an antiserum against a synthetic peptide corresponding to the 20 COOH-terminal amino acids of the E5 ORF. The E5 polypeptide is the smallest viral transforming protein yet characterized; it had an apparent size of 7 kilodaltons. The transforming polypeptide is encoded entirely within the second half of the E5 ORF and its predicted amino acid composition is very unusual; 68% of the amino acids are strongly hydrophobic and 34% are leucine. Cell fractionation studies localized this polypeptide predominantly to cellular membranes. 相似文献
18.
Association of human papillomavirus types 16 and 18 E6 proteins with p53 总被引：175，自引：0，他引：175
Human papillomavirus type 16 (HPV-16) is a DNA tumor virus that is associated with human anogenital cancers and encodes two transforming proteins, E6 and E7. The E7 protein has been shown to bind to the retinoblastoma tumor suppressor gene product, pRB. This study shows that the E6 protein of HPV-16 is capable of binding to the cellular p53 protein. The ability of the E6 proteins from different human papillomaviruses to form complexes with p53 was assayed and found to correlate with the in vivo clinical behavior and the in vitro transforming activity of these different papillomaviruses. The wild-type p53 protein has tumor suppressor properties and has also been found in association with large T antigen and the E1B 55-kilodalton protein in cells transformed by SV40 and by adenovirus type 5, respectively, providing further evidence that the human papillomaviruses, the adenoviruses, and SV40 may effect similar cellular pathways in transformation. 相似文献
19.
植物的耐盐性是一个多基因控制的复杂性状,将多个耐盐相关基因导入同一植物更有助于提高植物的耐盐能力.以玉米自交系H99、丹988的胚性愈伤组织为受体材料,通过愈伤组织对NaCl的敏感性试验,确定转化愈伤组织的适宜选择压,适宜愈伤组织转化的盐浓度为225 mmol/L.并对农杆菌遗传转化系统的条件进行了初步研究,用带有pCAMBIA-1301-CMO-BADH质粒的根癌农杆菌转化玉米愈伤组织,结果表明:采用EHA105的菌株振荡20h后,菌液OD值为0.5～0.6时侵染25 min为农杆菌转化的适宜条件.对移栽成活的36棵抗盐植株经PCR检测有2株呈阳性,阳性株率最高达到5.6％,初步证明目的基因已整合到玉米基因组中. 相似文献
20.
T-cell receptor beta-chain expression: dependence on relatively few variable region genes 总被引：41，自引：0，他引：41
M A Behlke D G Spinella H S Chou W Sha D L Hartl D Y Loh 《Science (New York, N.Y.)》1985,229(4713):566-570
Fifteen independently isolated complementary DNA clones that contain T-cell receptor (TCR) V beta genes were sequenced and found to represent 11 different V beta genes. When compared with known sequences, 14 different V beta genes could be defined from a total of 25 complementary DNA's; 11 clones therefore involved repeated usage of previously identified V beta's. Based on these data, we calculate a maximum likelihood estimate of the number of expressed germline V beta genes to be 18 with an upper 95 percent confidence bound of 30 genes. Southern blot analysis has shown that most of these genes belong to single element subfamilies which show very limited interstrain polymorphism. The TCR beta-chain diversity appears to be generated from a limited V beta gene pool primarily by extensive variability at the variable-diversity-joining (V-D-J) junctional site, with no evidence for the involvement of somatic hypermutation. 相似文献