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We report that the genomes of reindeer papillomavirus (RPV), European elk papillomavirus (EEPV), and deer papillomavirus (DPV) contain a short conserved translational open reading frame (ORF), E9, which is located between the E5 ORF and the early polyadenylation site. In RPV, DPV, and EEPV, E9 ORFs have the potential to encode extremely hydrophobic polypeptides of approximately 40 amino acids. In mouse C127 cells transformed by EEPV and RPV, there exists a unique, abundant mRNA species of approximately 700 nucleotides which has the capacity to encode an E9 polypeptide. This mRNA is transcribed from a previously unrecognized promoter at position 4030 in the EEPV genome. The EEPV E9 ORF exhibits weak transforming activity in C127 cells and primary rat embryo fibroblasts. We also show that EEPV E5 is the major oncogene in the EEPV genome when assayed in C127 cells, although it is less efficient in transformation than the E5 genes of bovine papillomavirus type 1, DPV, and RPV.  相似文献   

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For ethical, practical and economic reasons, scientists have traditionally relied on model organisms for biological research. Although model organisms do not always quite constitute the 'real thing', the significant advantages of their use contribute to making their study a viable alternative. The decision to use a specific model, particularly in large-scale studies such as genome projects, will be governed not only by biological consideration, but also by the prevailing financial and organizational infrastructure and expertise of the research community.  相似文献   

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Pregnancy-specific protein B (PSPB) was isolated, purified, and partially characterized from elk and moose placenta. The procedure, which was monitored by bovine PSPB (bPSPB) RIA, included homogenization and extraction in aqueous solution, acidic and ammonium sulfate precipitation, and ion exchange, gel filtration, and affinity chromatographies. The estimated molecular sizes of moose PSPB (mPSPB) were 58 kDa and 31 kDa, and of elk PSPB (ePSPB) were 57 kDa, 45 kDa, and 31 kDa by SDS-PAGE. The isoelectric points of mPSPB were 4.8, 6.6, and 6.7, and of ePSPB were 4.8, 4.9, 6.1, and 6.2 as determined by isoelectric focusing and two-dimensional gel electrophoresis. The carbohydrate contents of mPSPB and ePSPB were approximately 3.15% and 4.98%, respectively. Although ePSPB and mPSPB were recognized by anti-bPSPB in an Ouchterlony double immunodiffusion test, they were found to share identical epitopes and partial identities compared to bPSPB. After treatment at different temperatures (20-60 degrees C) for 1 h, the immunoreactivities of ePSPB and mPSPB in serum were very stable. Only ePSPB in serum treated at 60 degrees C lost some immunoreactivity. After alteration of serum pH (pH 3-11) for 2 h, the immunoreactivities of ePSPB and mPSPB became lower at pH 3 and 4, and remained stable from pH 5 to 11. These data show that moose and elk PSPB have properties similar to those of bovine and ovine PSPB.  相似文献   

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Moloney murine leukemia virus (MuLV) can be a potent inducer of promonocytic leukemias in mice that are undergoing a chronic inflammatory response. The neoplasms are, at least in part, associated with insertional mutagenesis of the c-myb locus. Evidence is presented for the existence of at least two genetic elements of the virus that are crucial to induction of this disease but are not required for viral replication in hematopoietic tissues or induction of lymphoid disease. These genetic elements were detected by testing the pathogenicity of recombinants between Moloney and Friend MuLVs, the latter of which is nonleukemic to myeloid cells under these conditions, and by testing Moloney MuLV-based viruses that have nonretroviral sequences inserted at specific endonuclease sites in their long terminal repeats (LTRs). Analysis of the Moloney/Friend recombinants showed that there are sequences within the structural gene domain of Moloney, but not Friend, MuLV that are necessary for promonocytic leukemia, whereas the LTRs of the MuLVs are equally effective for promonocytic tumor formation and insertional mutagenesis of the c-myb gene. Experiments with viruses which were mutagenized in the LTR by insertions demonstrated that there is a specific genetic element in the U3 region of the LTR of Moloney MuLV, upstream of the 75-base-pair enhancer which, when interrupted, results in loss of leukemogenicity for cells in the monocytic lineage but not cells in the lymphoid lineage. We conclude, therefore, that promonocytic leukemia induction, in Moloney MuLV-infected mice undergoing a chronic inflammatory response, requires specific sequences in the structural gene region of Moloney MuLV as well as other sequences in the regulatory region of the virus.  相似文献   

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The genetic analysis of the papillomaviruses has been hampered by the lack of mutants conditionally defective for viral biological activities. We report here the construction and characterization of a temperature-sensitive papillomavirus mutant. The mutation is predicted to insert the sequence Pro-Arg-Ser-Arg into the N-terminal half of the bovine papillomavirus type 1 (BPV1) ORF E2 protein, the major viral regulatory protein. The cloned mutant viral DNA displays temperature-sensitive defects in the induction of focus formation in mouse C127 cells, in its establishment as an extrachromosomal plasmid and in transactivation of a BPV1 enhancer. Genetic experiments confirm that this pleiotropic phenotype is caused by the insertion mutation in ORF E2 and that the transformation and replication defects of the mutant at 37 degrees C are corrected in trans by wild-type E2 gene activity. Most cell lines stably transformed by the mutant at 32.5 degrees C display a reduced ability to overgrow a monolayer of normal cells following temperature shift to 37 degrees C and the mutant viral DNA after temperature shift is present in decreased copy number and/or in an integrated state. These results provide strong genetic evidence that continued ORF E2 activity is required for maintenance of BPV1-induced transformation and for normal viral DNA replication.  相似文献   

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R Kulke  D DiMaio 《Journal of virology》1991,65(9):4943-4949
We determined the biological activities of the 44-amino-acid deer papillomavirus (DPV) E5 protein in mouse C127 cells. The DPV E5 gene can induce focus formation, stable and acute morphologic transformation, and DNA synthesis, and it activates the platelet-derived growth factor (PDGF) beta receptor as assessed by increased constitutive tyrosine phosphorylation of mature and precursor receptor forms. Thus, the DPV E5 protein has biological activities similar to those of the closely related E5 protein from bovine papillomavirus type 1. Moreover, like the bovine papillomavirus type 1 E5 protein, the DPV E5 protein shares a short region of sequence similarity with the B chain of PDGF. These results show that activation of the PDGF receptor is a general property of fibropapillomavirus E5 proteins, lending support to our previous proposal (L. Petti, L. Nilson, and D. DiMaio, EMBO J. 10:845-855, 1991) that activation of the PDGF receptor may play a central role in transformation of fibroblasts by E5 proteins.  相似文献   

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It has previously been shown that the Epstein-Barr virus (EBV) genome may be detected in some thymic tumors. We have investigated specimens of normal thymus, thymitis with lymphoid hyperplasia and a large spectrum of thymic epithelial tumors obtained from european patients for the presence of EBV genome by in situ hybridization and DNA-blotting methods. Cell lines established from seven of the thymic tumors were also tested for EBV. No EBV genome was demonstrated in any of the tumors examined, which included various types of thymoma and thymic carcinomas, nor in the non-neoplastic thymic specimens. However, unlike previous reports, no examples of lymphoepithelial-like thymic carcinoma, nor specimen from Asian patients were included in this study. We suggest that EBV is linked to a specific epithelial tumor type, namely the lymphoepithelial-like carcinoma, regardless of its site, and not to thymic tumors in general.  相似文献   

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It has previously been shown that the EpsteinBarr virus (EBV) genome may be detected in some thymic tumors. We have investigated specimens of normal thymus, thymitis with lymphoid hyperplasia and a large spectrum of thymic epithelial tumors obtained from european patients for the presence of EBV genome by in situ hybridization and DNA-blotting methods. Cell lines established from seven of the thymic tumors were also tested for EBV. No EBV genome was demonstrated in any of the tumors examined, which included various types of thymoma and thymic carcinomas, nor in the non-neoplastic thymic specimens. However, unlike previous reports, no examples of lymphoepithelial-like thymic carcinoma, nor specimen from Asian patients were included in this study. We suggest that EBV is linked to a specific epithelial tumor type, namely the lymphoepithelial-like carcinoma, regardless of its site, and not to thymic tumors in general. Supported by the SFB 172, C8, grant to BB and by the Deutsche Forschungsgemeinschaft, grant Ki 370/1-1  相似文献   

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The past decade has seen the determination of complete mitochondrial genome sequences from a taxonomically diverse set of organisms. These data have allowed an unprecedented understanding of the evolution of the mitochondrial genome in terms of gene content and order, as well as genome size and structure. In addition, phylogenetic reconstructions based on mitochondrial DNA (mtDNA)-encoded protein sequences have firmly established the identities of protistan relatives of the animal, fungal and plant lineages. Analysis of the mtDNAs of these protists has provided insight into the structure of the mitochondrial genome at the origin of these three, mainly multicellular, eukaryotic groups. Further research into mtDNAs of taxa ancestral and intermediate to currently characterized organisms will help to refine pathways and modes of mtDNA evolution, as well as provide valuable phylogenetic characters to assist in unraveling the deep branching order of all eukaryotes.  相似文献   

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Milk and meat from cattle and buffaloes contribute 45% of the global animal protein supply, followed by chickens (31%), and pigs (20%). In 2016, the global cattle population of 1.0 billion head produced 6.5 billion tons of cows’ milk, and 66 million tons of beef. In the past century, cattle breeding programs have greatly increased the yield per animal with a resultant decrease in the emissions intensity per unit of milk or beef, but this has not been true in all regions. Genome editing research in cattle to date has focused on disease resistance (e.g. tuberculosis), production (e.g. myostatin knockout; production of all-male offspring), elimination of allergens (e.g. beta-lactoglobulin knockout) and welfare (e.g. polled or hornlessness) traits. Modeling has revealed how the use of genome editing to introduce beneficial alleles into cattle breeds could maintain or even accelerate the rate of genetic gain accomplished by conventional breeding programs, and is a superior approach to the lengthy process of introgressing those same alleles from distant breeds. Genome editing could be used to precisely introduce useful alleles (e.g. heat tolerance, disease resistance) and haplotypes into native locally-adapted cattle breeds, thereby helping to improve their productivity. As with earlier genetic engineering approaches, whether breeders will be able to employ genome editing in cattle genetic improvement programs will very much depend upon global decisions around the regulatory framework and governance of genome editing for food animals.

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1. Tachykinin immunoreactivity has been localized, quantified and chromatographically-characterized in the brain, stomach, intestine and skin of Rana temporaria. 2. Antisera to mammalian substance P (SP) and neurokinin A (NKA) immunostained nerve fibres in all tissues except skin, and a population of mucosal endocrine cells in the intestinal epithelium. 3. Radioimmunoassay of tissue extracts identified SP immunoreactivity in all tissues but NKA immunoreactivity was restricted to the brain. 4. Chromatographic analysis of both frog tachykinins revealed that they possessed different physico-chemical properties than their mammalian counterparts.  相似文献   

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Plant Cell, Tissue and Organ Culture (PCTOC) - There was an error in the second author’s name in the original article. The name is correctly shown here.  相似文献   

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Haemophilus influenzae Rd is a gram-negative bacterium capable of natural DNA transformation. The competent state occurs naturally in late exponential growth or can be induced by a nutritional downshift or by transient anaerobiosis. The genes cya, crp, topA, and sxy (tfoX) are known to function in the regulation of competence development. The phosphoenolpyruvate:carbohydrate phosphotransferase system functions to maintain levels of cyclic AMP necessary for competence development but is not directly involved in regulation. The exact signal(s) for competence and the genes that mediate the signal(s) are still unknown. In an effort to find additional regulatory genes, H. influenzae Rd was mutated by using an in vitro Tn7 system and screened for mutants with a reduced ability to induce the competence-regulatory gene, comA. Insertions in atpA, a gene coding for the alpha subunit of the F1 cytoplasmic domain of the ATP synthase, reduce transformation frequencies about 20-fold and cause a significant reduction in expression of competence-regulatory genes, while the expression of constitutive competence genes is only minimally affected. In addition, we found that an insertion in atpB, which encodes the a subunit of the F0 membrane-spanning domain, has a similar effect on transformation frequencies.  相似文献   

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