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1.
A new class of endogenous human retroviral genomes   总被引：28，自引：0，他引：28  
Human DNA contains multiple copies of a novel class of endogenous retroviral genomes. Analysis of a human recombinant DNA clone (HLM-2) containing one such proviral genome revealed that it is a mosaic of retroviral-related sequences with the organization and length of known endogenous retroviral genomes. The HLM-2 long terminal repeat hybridized with the long terminal repeat of the squirrel monkey virus, a type D retrovirus. The HLM-2 gag and pol genes share extensive nucleotide sequence homology with those of the M432 retrovirus (a type A-related retrovirus), mouse mammary tumor virus (a type B retrovirus), and the avian Rous sarcoma virus (a type C retrovirus). Nucleotide sequence analysis revealed regions in the HLM-2 pol gene that were as much as 70 percent identical to the mouse mammary tumor virus pol gene. A portion of the putative HLM-2 env gene hybridized with the corresponding region of the M432 viral genome.  相似文献   

2.
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3.
The integration of retroviral genomes into cellular DNA can induce mutations by altering the expression of nearby cellular genes and can serve to identify the gene affected. The construction of a retrovirus that stably carries a suppressor transfer RNA gene from Escherichia coli has allowed facile recovery of the viral genome in vectors marked with amber mutations. This virus can be used for rapid isolation of cellular sequences at the site of proviral insertion.  相似文献   

4.
New method for detecting cellular transforming genes   总被引：24，自引：0，他引：24  
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   

5.
Human DNA contains many copies of endogenous retroviral sequences. Characterization of molecular clones of these structures reveals the existence of two related families. One family consists of full-length (8.8 kilobases) proviral structures, with typical long terminal repeates (LTR's). The other family consists of structures, which contain only 4.1 kilobases of gag-pol sequences, bounded by a tandem array of imperfect repeats 72 to 76 base pairs in length. Typical LTR sequences that exist as solitary elements in the genome were cloned and characterized.  相似文献   

6.
HIV-1 integrates into the host chromosome and persists as a provirus flanked by long terminal repeats (LTRs). To date, treatment regimens primarily target the virus enzymes or virus-cell fusion, but not the integrated provirus. We report here the substrate-linked protein evolution of a tailored recombinase that recognizes an asymmetric sequence within an HIV-1 LTR. This evolved recombinase efficiently excised integrated HIV proviral DNA from the genome of infected cells. Although a long way from use in the clinic, we speculate that this type of technology might be adapted in future antiretroviral therapies, among other possible uses.  相似文献   

7.
The high degree of similarity between the mouse and human genomes is demonstrated through analysis of the sequence of mouse chromosome 16 (Mmu 16), which was obtained as part of a whole-genome shotgun assembly of the mouse genome. The mouse genome is about 10% smaller than the human genome, owing to a lower repetitive DNA content. Comparison of the structure and protein-coding potential of Mmu 16 with that of the homologous segments of the human genome identifies regions of conserved synteny with human chromosomes (Hsa) 3, 8, 12, 16, 21, and 22. Gene content and order are highly conserved between Mmu 16 and the syntenic blocks of the human genome. Of the 731 predicted genes on Mmu 16, 509 align with orthologs on the corresponding portions of the human genome, 44 are likely paralogous to these genes, and 164 genes have homologs elsewhere in the human genome; there are 14 genes for which we could find no human counterpart.  相似文献   

8.
By means of a selective DNA amplification technique called polymerase chain reaction, proviral sequences of the human immunodeficiency virus (HIV-1) were identified directly in DNA isolated from peripheral blood mononuclear cells (PBMCs) of persons seropositive but not in DNA isolated from PBMCs of persons seronegative for the virus. Primer pairs from multiple regions of the HIV-1 genome were used to achieve maximum sensitivity of provirus detection. HIV-1 sequences were detected in 100% of DNA specimens from seropositive, homosexual men from whom the virus was isolated by coculture, but in none of the DNA specimens from a control group of seronegative, virus culture-negative persons. However, HIV-1 sequences were detected in 64% of DNA specimens from seropositive, virus culture-negative homosexual men. This method of DNA amplification made it possible to obtain results within 3 days, whereas virus isolation takes up to 3 to 4 weeks. The method may therefore be used to complement or replace virus isolation as a routine means of determining HIV-1 infection.  相似文献   

9.
Transgenic mice containing intact copies of the human immunodeficiency virus (HIV) proviral DNA were constructed. Founder animals were not viremic for HIV and remained healthy during a 9-month observation period. After being mated with nontransgenic animals, one founder mouse (No. 13) gave rise to F1 progeny that developed a disease syndrome characterized by marked epidermal hyperplasia, lymphadenopathy, splenomegaly, pulmonary lymphoid infiltrates, growth retardation, and death by day 25 of life. Infectious HIV, indistinguishable from parental virus by immunoblot analysis, was recovered from the spleen, lymph nodes, and skin of five of five affected animals.  相似文献   

10.
Three types of tumors termed plasmacytomas (ABPC's), lymphosarcomas (ABLS's), and plasmacytoid lymphosarcomas (ABPL's) arise in BALB/c mice treated with pristane and Abelson murine leukemia virus (A-MuLV). While most ABPC's and BLS's contain integrated A-MuLV proviral genome and synthesize the v-abl RNA, most ABPL's do not. The ABPL tumors were examined for the expression of other oncogenes that may be associated with their transformed state, in the absence of transforming virus. These tumors expressed abundant c-myb RNA of unusually large size and showed DNA rearrangements of the c-myb locus.  相似文献   

11.
利用精子载体法制备转基因动物是一种简便、可行的研究和应用方法,但精子结合并内化转运外源DNA却具有非常复杂的机制。从精子结合外源DNA的物质基础及分子机制,外源DNA在精子细胞中的存在和降解等方面展开探讨,并着重探讨了外源DNA在精子基因组中的整合机制。另外,基于理论研究的进展讨论了转基因动物的制备策略。  相似文献   

12.
Techniques of gene amplification, molecular cloning, and sequence analysis were used to test for the presence of sequences related to human T-lymphotropic virus type I (HTLV-I) in peripheral blood mononuclear cells of six patients with multiple sclerosis (MS) and 20 normal individuals. HTLV-I sequences were detected in all six MS patients and in one individual from the control group by DNA blot analysis and molecular cloning of amplified DNAs. The viral sequence in MS patients were associated with adherent cell populations consisting predominantly of monocytes and macrophages. Molecular cloning and nucleotide sequence analysis indicated that these amplified viral sequences were related to the HTLV-I proviral genome.  相似文献   

13.
Transcription of nonrepeated DNA in mouse brain   总被引：10，自引：0，他引：10  
Under normal conditions of DNA renaturation, about 60 percent of mouse DNA fragments renature at a rate consistent with their being present only once per sperm. These nonrepeated sequences (also called single-copy or unique) may be used in RNA-DNA hybridization experiments to provide quantitative estimates of RNA diversity. About 10 percent of the mouse single-copy sequences are transcribed in mouse brain tissue. Estimates of about 3 percent were obtained for mouse liver and kidney RNA's. If only one of the complementary DNA strands is transcribed, this hybridization value implies that the equivalent of at least 300,000 different sequences of 1000 nucleotides are expressed in mouse brain tissue. It is suggested that the large amount of DNA in mammals is functionally important, and that a substantial proportion of the genome is expressed in the brain.  相似文献   

14.
粒细胞-巨噬细胞集落刺激因子(GM-CSF)是机体免疫系统的重要细胞因子,具有生物佐剂作用,为研究GM-CSF的生物佐剂作用,本试验通过RT-PCR方法从小鼠脾脏细胞中扩增小鼠GM-CSF的cDNA,并将其插入到pcDNA3.1质粒中,构建成GM-CSF真核表达载体pcDNA3.1-GMCSF,并在真核细胞进行了瞬时表达。结果表明,本研究扩增的小鼠GM-CSF基因序列与GenBank序列完全一致,表达载体经脂质体介导转染HEK293T细胞,表达产物经western-blot检测,证明GM-CSF能够在HEK293T细胞中进行分泌表达。这为今后研究GM-CSF在动物疫苗,特别是DNA疫苗中的生物佐剂作用创造了必要的条件。  相似文献   

15.
Research on the mouse genome lurched into the fast lane last week, as private donors joined the U.S. government to step on the gas. A public-private consortium announced on 6 October that it's kicking $58 million into a new fund that will pay to sequence the DNA of the "black six" (C57BL/6J) strain of laboratory mouse. The consortium aims to produce a draft version of the genome by the end of February.  相似文献   

16.
The recent development of genome editing technologies has given researchers unprecedented power to alter DNA sequences at chosen genomic loci, thereby generating various genetically edited animal models. This mini-review briefly summarizes the development of major genome editing tools, focusing on the application of these tools to generate animal models in multiple species.  相似文献   

17.
A detailed schematic representation of high-resolution G-banding patterns was prepared from elongated and finely banded mitotic chromosomes of the mouse. Such chromosomes can be obtained from both animal tissue and cell lines by a simple protocol, facilitating precise demarcation of breakpoints in chromosome rearrangements and aiding in the sublocalization of genes. Regions of subbanding homology were observed between human and mouse chromosomal segments known to have conserved gene assignments, an indication that, at the cytogenetic level, extensive regions of the mammalian genome may remain intact after 60 million years of species divergence.  相似文献   

18.
The acquired immune deficiency syndrome (AIDS) is characterized by T-lymphocyte dysfunction and is frequently accompanied by opportunistic infections and Kaposi's sarcoma. Human T-cell leukemia virus (HTLV) is associated with T-cell malignancies and can transform T lymphocytes in vitro. In an attempt to find evidence of HTLV infection in patients with AIDS, DNA from samples of peripheral blood lymphocytes from 33 AIDS patients was analyzed by Southern blot-hybridization with a radiolabeled cloned HTLV DNA probe. Analysis of DNA from both the fresh (uncultured) lymphocytes and from T cells cultured with T-cell growth factor revealed the presence of integrated HTLV proviral sequences in lymphocytes from two of the patients, both of whom had antibody to HTLV. The proviral sequences could not be detected in blood samples obtained from these individuals at a later date, consistent with the possibility that the population of infected cells had become depleted.  相似文献   

19.
A mouse model of the aniridia-Wilms tumor deletion syndrome   总被引：11，自引：0，他引：11  
Deletion of chromosome 11p13 in humans produces the WAGR syndrome, consisting of aniridia (an absence or malformation of the iris), Wilms tumor (nephroblastoma), genitourinary malformations, and mental retardation. An interspecies backcross between Mus musculus/domesticus and Mus spretus was made in order to map the homologous chromosomal region in the mouse genome and to define an animal model of this syndrome. Nine evolutionarily conserved DNA clones from proximal human 11p were localized on mouse chromosome 2 near Small-eyes (Sey), a semidominant mutation that is phenotypically similar to aniridia. Analysis of Dickie's Small-eye (SeyDey), a poorly viable allele that has pleiotropic effects, revealed the deletion of three clones, f3, f8, and k13, which encompass the aniridia (AN2) and Wilms tumor susceptibility genes in man. Unlike their human counterparts, SeyDey/+ mice do not develop nephroblastomas. These findings suggest that the Small-eye defect is genetically equivalent to human aniridia, but that loss of the murine homolog of the Wilms tumor gene is not sufficient for tumor initiation. A comparison among Sey alleles suggests that the AN2 gene product is required for induction of the lens and nasal placodes.  相似文献   

20.
Altering the genome by homologous recombination   总被引：167，自引：0，他引：167  
Homologous recombination between DNA sequences residing in the chromosome and newly introduced, cloned DNA sequences (gene targeting) allows the transfer of any modification of the cloned gene into the genome of a living cell. This article discusses the current status of gene targeting with particular emphasis on germ line modification of the mouse genome, and describes the different methods so far employed to identify those rare embryonic stem cells in which the desired targeting event has occurred.  相似文献   

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