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1.
A method was developed for selectively isolating genes from localized regions of the human genome that are contained in interspecific hybrid cells. Complementary human DNA was prepared from a human-rodent somatic cell hybrid that contained less than 1% human DNA, by using consensus 5' intron splice sequences as primers. These primers would select immature, unspliced messenger RNA (still retaining species-specific repeat sequences) as templates. Screening a derived complementary DNA library for human repeat sequences resulted in the isolation of human clones at the anticipated frequency with characteristics expected of exons of transcribed human genes--single copy sequences that hybridized to discrete bands on Northern (RNA) blots. 相似文献
2.
Small nuclear RNA U2 is base-paired to heterogeneous nuclear RNA 总被引：18，自引：0，他引：18
Eukaryotic cells contain a set of low molecular weight nuclear RNA's. One of the more abundant of these is termed U2 RNA. The possibility that U2 RNA is hydrogen-bonded to complementary sequences in other nuclear RNA's was investigated. Cultured human (HeLa) cells were treated with a psoralen derivative that cross-links RNA chains that are base-paired with one another. High molecular weight heterogeneous nuclear RNA was isolated under denaturing conditions, and the psoralen cross-links were reversed. Electrophoresis of the released RNA and hybridization with a human cloned U2 DNA probe revealed that U2 is hydrogen-bonded to complementary sequences in heterogeneous nuclear RNA in vivo. In contrast, U2 RNA is not base-paired with nucleolar RNA, which contains the precursors of ribosomal RNA. The results suggest that U2 RNA participates in messenger RNA processing in the nucleus. 相似文献
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Structure of the human interleukin-2 receptor gene 总被引：38，自引：0，他引：38
W J Leonard J M Depper M Kanehisa M Kr?nke N J Peffer P B Svetlik M Sullivan W C Greene 《Science (New York, N.Y.)》1985,230(4726):633-639
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Genomic analysis of the human B-lymphotropic virus (HBLV) 总被引：18，自引：0，他引：18
S F Josephs S Z Salahuddin D V Ablashi F Schachter F Wong-Staal R C Gallo 《Science (New York, N.Y.)》1986,234(4776):601-603
The human B-lymphotropic virus (HBLV) has a double-stranded DNA genome of greater than 110 kilobase pairs, which is consistent with its morphological classification as a herpesvirus. A 9000-base pair cloned probe of HBLV detected specific sequences in DNA and RNA of infected cells but did not hybridize to the genomic DNA of other human herpesviruses including the Epstein-Barr virus, human cytomegalovirus, herpes simplex type I, and varicella-zoster virus. Conversely, while probes obtained from each of the known human herpesvirus readily detected the homologous viral DNA, they did not hybridize to genomic HBLV DNA. This evidence, in addition to serological and morphological distinctions and the biological effects of this virus demonstrate that HBLV is a novel human herpesvirus. 相似文献
5.
Human multidrug-resistant cell lines: increased mdr1 expression can precede gene amplification 总被引：40，自引：0，他引：40
D W Shen A Fojo J E Chin I B Roninson N Richert I Pastan M M Gottesman 《Science (New York, N.Y.)》1986,232(4750):643-645
The development of simultaneous resistance to multiple structurally unrelated drugs is a major impediment to cancer chemotherapy. Multidrug resistance in human KB carcinoma cells selected in colchicine, vinblastine, or Adriamycin is associated with amplification of specific DNA sequences (the multidrug resistance locus, mdr1). During colchicine selection resistance is initially accompanied by elevated expression of a 4.5-kilobase mdr1 messenger RNA (mRNA) without amplification of the corresponding genomic sequences. During selection for increased levels of resistance, expression of this mRNA is increased simultaneously with amplification of mdr1 DNA. Increased expression and amplification of mdr1 sequences were also found in multidrug-resistant sublines of human leukemia and ovarian carcinoma cells. These results suggest that increased expression of mdr1 mRNA is a common mechanism for multidrug resistance in human cells. Activation of the mdr1 gene by mutations or epigenetic changes may precede its amplification during the development of resistance. 相似文献
6.
Correlation of glucocorticoid receptor binding sites on MMTV proviral DNA with hormone inducible transcription 总被引：9，自引：0，他引：9
M Pfahl D McGinnis M Hendricks B Groner N E Hynes 《Science (New York, N.Y.)》1983,222(4630):1341-1343
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Retroviral DNA integration directed by HIV integration protein in vitro 总被引：65，自引：0，他引：65
Efficient retroviral growth requires integration of a DNA copy of the viral RNA genome into a chromosome of the host. As a first step in analyzing the mechanism of integration of human immunodeficiency virus (HIV) DNA, a cell-free system was established that models the integration reaction. The in vitro system depends on the HIV integration (IN) protein, which was partially purified from insect cells engineered to express IN protein in large quantities. Integration was detected in a biological assay that scores the insertion of a linear DNA containing HIV terminal sequences into a lambda DNA target. Some integration products generated in this assay contained five-base pair duplications of the target DNA at the recombination junctions, a characteristic of HIV integration in vivo; the remaining products contained aberrant junctional sequences that may have been produced in a variation of the normal reaction. These results indicate that HIV IN protein is the only viral protein required to insert model HIV DNA sequences into a target DNA in vitro. 相似文献
9.
Amplification and enhanced expression of the epidermal growth factor receptor gene in A431 human carcinoma cells 总被引：46，自引：0，他引：46
G T Merlino Y H Xu S Ishii A J Clark K Semba K Toyoshima T Yamamoto I Pastan 《Science (New York, N.Y.)》1984,224(4647):417-419
The sequence of the human epidermal growth factor (EGF) receptor shows great homology with the avian erythroblastosis virus v-erb B oncogene, raising the possibility that the receptor gene is identical to the c-erb B protooncogene. Human A431 epidermoid carcinoma cells, which have an unusually high number of EGF receptors, were examined to determine whether elevated EGF receptor levels correlate with gene amplification. Southern blots of genomic DNA's from A431 and other human cell lines were probed with either a v-erb B gene fragment or a human EGF receptor complementary DNA clone (pE7), previously isolated from an A431 complementary DNA library. When either probe was used to analyze Eco RI- or Hind III-generated DNA fragments, EGF receptor DNA sequences were amplified about 30-fold in A431. Differences in the banding pattern of A431 DNA fragments relative to normal fibroblast DNA indicate the occurrence of a rearrangement in the region of the receptor gene. Furthermore, A431 cells contain a characteristic, prominent 2.9-kilobase RNA. These results are consistent with the hypothesis that, in A431 cells, gene amplification, possibly associated with a translocation event, may result in the overproduction of EGF receptor protein or the appearance of the transformed phenotype (or both). 相似文献
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Existence of high abundance antiproliferative mRNA's in senescent human diploid fibroblasts 总被引：21，自引：0，他引：21
C K Lumpkin J K McClung O M Pereira-Smith J R Smith 《Science (New York, N.Y.)》1986,232(4748):393-395
Polyadenylated RNA isolated from senescent human diploid fibroblasts (HDF) inhibited DNA synthesis in proliferation-competent cells after microinjection, whereas polyadenylated RNA from young HDF had no inhibitory effect. Polyadenylated RNA from young cells made quiescent by removal of serum growth factors had a slight inhibitory effect on DNA synthesis. The abundance level of inhibitor messenger RNA (mRNA) from senescent cells was estimated at 0.8 and that of quiescent cells at 0.005 percent. These results demonstrate the existence of one or more antiproliferative mRNA's in nonproliferating normal human cells; these RNA's code for factors that either work antagonistically to initiators of DNA synthesis or regulate the expression of the initiators in some way. The abundance level of the inhibitory mRNA in senescent cells indicates the feasibility of developing a complementary DNA probe that will be useful in studying cell cycle control mechanisms. 相似文献
12.
Doubls-helical polynucleotides: immunochemical recognition of differing conformations 总被引：9，自引：0，他引：9
B D Stollar 《Science (New York, N.Y.)》1970,169(945):609-611
Rabbit antibodies to double-helical RNA react by complement fixation with synthetic or natural double-strand RNA but not with native DNA. In turn, human (from systemic lupus erythematosus patients) antibodies to native DNA do not react with double-strand RNA. Both types of antibodies show cross-reactions (from 1 percent to 50 percent) with RNA-DNA hybrids, but antibodies to the hybrids do not react at all with double-strand RNA or with native DNA. Antibodies to polydeoxyguanylate.polydeoxycytidylate also failed to react with native DNA. 相似文献
13.
Binding of the Sp1 transcription factor by the human Harvey ras1 proto-oncogene promoter 总被引：34，自引：0，他引：34
S Ishii J T Kadonaga R Tjian J N Brady G T Merlino I Pastan 《Science (New York, N.Y.)》1986,232(4756):1410-1413
14.
Suppression of human colorectal carcinoma cell growth by wild-type p53 总被引：219，自引：0，他引：219
S J Baker S Markowitz E R Fearon J K Willson B Vogelstein 《Science (New York, N.Y.)》1990,249(4971):912-915
Mutations of the p53 gene occur commonly in colorectal carcinomas and the wild-type p53 allele is often concomitantly deleted. These findings suggest that the wild-type gene may act as a suppressor of colorectal carcinoma cell growth. To test this hypothesis, wild-type or mutant human p53 genes were transfected into human colorectal carcinoma cell lines. Cells transfected with the wild-type gene formed colonies five- to tenfold less efficiently than those transfected with a mutant p53 gene. In those colonies that did form after wild-type gene transfection, the p53 sequences were found to be deleted or rearranged, or both, and no exogenous p53 messenger RNA expression was observed. In contrast, transfection with the wild-type gene had no apparent effect on the growth of epithelial cells derived from a benign colorectal tumor that had only wild-type p53 alleles. Immunocytochemical techniques demonstrated that carcinoma cells expressing the wild-type gene did not progress through the cell cycle, as evidenced by their failure to incorporate thymidine into DNA. These studies show that the wild-type gene can specifically suppress the growth of human colorectal carcinoma cells in vitro and that an in vivo-derived mutation resulting in a single conservative amino acid substitution in the p53 gene product abrogates this suppressive ability. 相似文献
15.
Gene transfer and expression of human phenylalanine hydroxylase 总被引：18，自引：0，他引：18
Phenylketonuria (PKU) is caused by a genetic deficiency of the enzyme phenylalanine hydroxylase (PAH). A full-length complementary DNA clone of human PAH was inserted into a eukaryotic expression vector and transferred into mouse NIH3T3 cells which do not normally express PAH. The transformed mouse cells expressed PAH messenger RNA, immunoreactive protein, and enzymatic activity that are characteristic of the normal human liver products, demonstrating that a single gene contains all of the necessary genetic information to code for functional PAH. These results support the use of the human PAH probe in prenatal diagnosis and detection of carriers, to provide new opportunities for the biochemical characterization of normal and mutant enzymes, and in the investigation of alternative genetic therapies for PKU. 相似文献
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Genetic variation in the human insulin gene 总被引：22，自引：0，他引：22
Four recombinant lambda phages containing nucleotide sequences complementary to a cloned human preproinsulin DNA probe have been isolated from human DNA. Restriction analyses in conjunction with Southern hybridizations reveal two types of gene sequences. One isolate of each type was subjected to complete nucleotide sequence determination. The sequences contain the entire preproinsulin messenger RNA region, two intervening sequence. 260 nucleotides upstream from the messenger RNA capping site, and 35 nucleotides beyond the polyadenylate attachment site. Our results strongly suggest that these two gene types are allelic variants of a single insulin gene. 相似文献
18.
Li et al. (Research Articles, 1 July 2011, p. 53; published online 19 May 2011) reported large numbers of differences between DNA and messenger RNA in human cells, indicating unprecedented levels of RNA editing, and including sequence changes not produced by any of the known RNA editing mechanisms. However, common sources of systematic errors in high-throughput sequencing technology, which were not properly accounted for in this study, explain most of the claimed differences. 相似文献
19.
以浙江近海三疣梭子蟹大螯肌肉的线粒体DNA作为模板,对4群体共67个个体的控制区（D-loop）序列进行了PCR扩增。通过对PCR产物进行双向测序,最终得到了控制区3’端的rRNA部分序列（64 bp）、D-loop全序列（1179 bp）及控制区5’端tRNA-Ile部分序列（73 bp）。经DNASP软件分析得知,67个D-loop序列定义了65个单倍型,在65个单倍型中,除去插入/缺失位点,所有单倍型共检测到344个多态位点,主要发生在D-loop序列的中间区域;D-loop序列检测到26个插入或缺失位点,碱基插入主要发生在中央后端区域,以13 bp重复片断插入的形式进行。每个个体含有0～3个连续重复片断。通过对三疣梭子蟹的遗传多样性分析发现,D-loop序列的单倍型多样性为0.982～1.000,核苷酸多样性指数为0.02770～0.03633,平均核苷酸差异数为31.790～43.304。综合分析,三个成蟹群体的遗传多样性相近,都低于仔蟹的遗传多样性,说明经过遗传育种,可以提高三疣梭子蟹的种质情况,真正实现对三疣梭子蟹的科学利用。 相似文献
20.
Human sarcomas contain RNA related to the RNA of a mouse leukemia virus 总被引：20，自引：0，他引：20
Labeled DNA complementary to the RNA of the Rauscher leukemia virus was hybridized with RNA from the polysome fraction of human sarcomas. Eighteen out of 25 specimens contained RNA possessing homology to the RNA of the mouse leukemia virus but not to that of the unrelated viruses causing mammary tumors in mice or myeloblastosis in chickens. Further, no normal adult or fetal tissues showed significant amounts of RNA specific to mouse leukemia virus. It appears that human sarcomas contain RNA sequences homologous to those found in an agent related to a virus known to cause sarcomas in mice. 相似文献