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R H Miller 《Science (New York, N.Y.)》1988,239(4846):1420-1422
The genome of the human immunodeficiency virus (HIV) is known to contain eight open reading frames (ORFs) on the minus strand of the double-stranded DNA replicative intermediate. Data presented here indicate that the DNA plus strand of HIV contains a previously unidentified ORF in a region complementary to the envelope gene sequence. This ORF could encode a protein of approximately 190 amino acid residues with a relative molecular mass of 20 kilodaltons if translation began from the first initiation codon. The predicted protein is highly hydrophobic and thus could be membrane associated. It is possible, therefore, that the HIV genome encodes a protein on antisense messenger RNA.  相似文献   

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Erythrocyte transfer RNA: change during chick development   总被引:10,自引:0,他引:10  
Radioactive aminoacyl transfer RNA's isolated from erythrocytes in the blood of 4-day-old chick embryos and from reticulocytes of adult chickens were analyzed by chromatography on methylated albumin kieselguhr and freon columns. Embryonic and adult methionyl transfer RNA's showed qualitative and quantitative differences in both chromatographic systems. The patterns for arginyl, seryl, and tyrosyl transfer RNA's in the two cell types were similar, while the leucyl transfer RNA patterns suggested a difference.  相似文献   

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Differential gene expression in the gastrula of Xenopus laevis   总被引:39,自引:0,他引:39  
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Cello J  Paul AV  Wimmer E 《Science (New York, N.Y.)》2002,297(5583):1016-1018
Full-length poliovirus complementary DNA (cDNA) was synthesized by assembling oligonucleotides of plus and minus strand polarity. The synthetic poliovirus cDNA was transcribed by RNA polymerase into viral RNA, which translated and replicated in a cell-free extract, resulting in the de novo synthesis of infectious poliovirus. Experiments in tissue culture using neutralizing antibodies and CD155 receptor-specific antibodies and neurovirulence tests in CD155 transgenic mice confirmed that the synthetic virus had biochemical and pathogenic characteristics of poliovirus. Our results show that it is possible to synthesize an infectious agent by in vitro chemical-biochemical means solely by following instructions from a written sequence.  相似文献   

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Based on physical and chemical determinations, the mnolecular weight of the type 4 adeno-satellite virus is 5.4 X 10(6) daltons, and the virion contains 1.4 X 10(6) daltons of DNA. Denaturation and renaturation studies indicate that the viral genome is a single-stranded DNA molecule and that each virion contains either a minus or a plus strand. Upon extraction, the minus and plus strands unite to form double-stranded DNA molecules with no obvious excess of unpaired strands.  相似文献   

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During normal mouse development the relative amounts of two types of U1 small nuclear RNA's (U1 RNA) change significantly. Fetal tissues have comparable levels of the two major types of mouse U1 RNA's, mU1a and mU1b, whereas most differentiated adult tissues contain only mU1a RNA's. Those adult tissues that also accumulate detectable amounts of embryonic (mU1b) RNA's (for example, testis, spleen, and thymus) contain a significant proportion of stem cells capable of further differentiation. Several strains of mice express minor sequence variants of U1 RNA's that are subject to the same developmental controls as the major types of adult and embryonic U1 RNA. The differential accumulation of embryonic U1 RNA's may influence the pattern of gene expression during early development and differentiation.  相似文献   

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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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Translation of unspliced transcripts after heat shock   总被引:19,自引:0,他引:19  
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以番鸭脑垂体为材料,用Trizol法提取总RNA,用Superscipt Ⅱ-RT合成第一链cDNA,RNase H和DNA Polymerase合成第二链cDNA,最后用EcoR Ⅰ/Mse Ⅰ分步酶切cDNA各2h,经T4连接酶合成双链cDNA,预扩增反应后产物稀释40倍进行选择性扩增反应.经1%琼脂糖电泳及6%变...  相似文献   

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When S(35)-labeled soluble RNA from Escherichia coli K 38 is subjected to gel filtration, four fractions of RNA are obtained by elution. Only one RNA fraction, the transfer RNA, contains sulfur, presumably as thionucleotides. Treatment with ribonuclease suggests that the incorporated sulfur is an integral part of the polynucleotide chain; digestion with alkali yields a mixture of products containing sulfur, the major one being eluted in a position similar to uridine diphosphate upon Dowex-l chromatography. Analysis by countercurrent distribution of S(35)-labeledtransfer RNA from E. coli B reveals that the incorporated sulfur is found in many RNA's that accept amino acids, but the possibility remains that not all acceptor RNA's contain sulfur.  相似文献   

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用2对已发表的引物和1对自行设计的引物对同一IBVH120株进行RT-PCR,分别获得了S1基因上与引物设计相一致的1720bp,228bp,602bp,的扩增片段。用自行设计的引物对7个毒株(H120,H52,M41,Conn,Gray,T,Holte)和5个分离株(宜毒,上毒,云毒,HK,118)的含毒尿囊液或纯化病毒进行RT-PCR。结果除Holte株,2个分离株(宜毒,云毒)外,其余均被成功地扩增出602bp的片段。将IBVH120株06kbPCR产物用Digoxigenin标记为探针,分别与上述各IBV毒株的核酸及其扩增产物进行核酸杂交,均呈现阳性反应,而该探针不与IBDV和NDV的DNA,EDS-76病毒的DNA及正常鸡胚尿囊液抽提物反应。RT-PCR和核酸杂交技术提供了直接从尿囊液中快速检测出病毒,作为诊断IBV的新方法。  相似文献   

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Examination of the amino acid sequences of human cytochrome c and the alpha-chain variant of human hemoglobin Constant Spring has revealed the possiblity for base-paired hairpin loops in the messenger RNA's for these proteins. A similar analysis of the bacteriophage R17 coat protein suggests an additional unobserved loop in the R17 RNA. If such loops are present in messenger RNA's generally, it would suggest that DNA has more than one stable base-paired conformation.  相似文献   

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Cross-linked transfer RNA functions in all steps of the translation process   总被引:1,自引:0,他引:1  
A specific photochemical reaction between 4-thiouridine and cytosine cross-links two arms of transfer RNA. This cross-link, introduced into phenylalanine transfer RNA and arginine transfer RNA, limits the conformational freedom of the molecule. Both modified transfer RNA's are capable of functioning in all steps of protein synthesis with this restraint on allowable conformations.  相似文献   

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