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To generate new chromosome 21 markers in a region that is critical for the pathogenesis of Down syndrome (D21S55-MX1), we used pulsed field gel electrophoresis (PFGE) to isolate a 600-kb NruI DNA fragment from the WA17 hybrid cell line, which has retained chromosome 21 as the only human material. This fragment, which contains the oncogene ETS2, was used to construct a partial genomic library. Among the 14 unique sequences that were isolated, 3 were polymorphic markers and contained sequences that are conserved in mammals. Five of these markers mapped on the ETS2-containing NruI fragment and allowed us to define an 800-kb high-resolution PFGE map.  相似文献   
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Summary The human genome contains a large number of interspersed simple repeat sequences that are variable in length and can therefore serve as highly informative, polymorphic markers. Typing procedures include conventional multilocus and single locus probing, and polymerase chain reaction aided analysis. We have identified simple sequences in a cosmid clone stemming from the human Y chromosome and consisting of (gata)n repeats. We have compared these with two equivalent simple repeat loci from chromosome 12. After amplifying the tandemly repeated motifs, we detected between four and eight different alleles at each of the three loci. Codominant inheritance of the alleles was established in family studies and the informativity of the simple repeat loci was determined by typing unrelated individuals. The polymorphisms are suitable for application in linkage studies, practical forensic case work, deficiency cases in paternity determination, and for studying ethnological questions. The mutational mechanisms that bring about changes in simple repeats located both on the autosomes and on the sex chromosomes, are discussed.Professor Dr. Otto Prokop (Humboldt-Universität Berlin) on the occasion of his 70th birthday  相似文献   
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Previous reports have described antigens that are recognized on human melanoma cells by autologous cytolytic T lymphocytes (CTL). The genes coding for a number of these antigens have been identified. Here we report the cloning of a gene that codes for an antigen recognized by autologous CTL on a human renal carcinoma cell line. This antigen is presented byHLA-B7 and is encoded by a new gene that we have namedRAGE1. No expression ofRAGE1 was found in normal tissues other than retina. RAGE1 expression was found in only one of 57 renal cell carcinoma samples, and also in some sarcomas, infiltrating bladder carcinomas, and melanomas. This represents the first identification of an antigen recognized by autologous CTL on a renal tumor.  相似文献   
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A cDNA encoding the mature, chloroplast-localized carbonic anhydrase in pea has been expressed inE. coli. The enzyme is fully active and yields of up to 20% of the total soluble protein can be obtained from the bacteria. This expression system was used to monitor the effects of site-directed mutagenesis of seven residues found within conserved regions in the pea carbonic anhydrase amino acid sequence. The effects of these modifications are discussed with respect to the potential of various amino acids to act as sites for zinc coordination or intramolecular proton shuttles.  相似文献   
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Journal of Plant Growth Regulation - Auxin is a hormone that delays ripening in part by reducing anthocyanin content and impairing color development. Auxin content declines during the ripening...  相似文献   
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An in frame gene fusion containing the coding region for mature -lactamase and the 3-end of hylA encoding the haemolysin secretion signal, was constructed under the control of a lac promoter. The resulting 53 kDa hybrid protein was specifically secreted to the external medium in the presence of the haemolysin translocator proteins, HlyB and HlyD. The specific activity of the -lactamase portion of the secreted protein (measured by the hydrolysis of penicillin G), approximately 1 U/g protein, was close to that of authentic, purified TEM--lactamase. This is an important example of a hybrid protein that is enzymatically active, and secreted via the haemolysin pathway. Previous studies have indicated that haemolysin is secreted directly into the medium, bypassing the periplasm, to which -lactamase is normally targeted. This study indicated, therefore, that normal folding of an active -lactamase, can occur, at least when fused to the HlyA C-terminus, without the necessity of entering the periplasm. Despite the secretion of approximately 5 g/ml levels of the active -lactamase fusion into the medium, there was maximally only a 50% detectable increase in the LD50 for resistance to ampicillin at the individual cell level. This result suggests that, normally, resistance to ampicillin requires a high concentration of the enzyme close to killing targets, i.e. in the periplasm, in order to achieve significant levels of protection.These authors made an equal contribution to this work  相似文献   
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Abstract: As cerebral neurons express the dopamine D1 receptor positively coupled with adenylyl cyclase, together with the D3 receptor, we have investigated in a heterologous cell expression system the relationships of cyclic AMP with D3 receptor signaling pathways. In NG108-15 cells transfected with the human D3 receptor cDNA, dopamine, quinpirole, and other dopamine receptor agonists inhibited cyclic AMP accumulation induced by forskolin. Quinpirole also increased mitogenesis, assessed by measuring [3H]thymidine incorporation. This effect was blocked partially by genistein, a tyrosine kinase inhibitor. Forskolin enhanced by 50–75% the quinpirole-induced [3H]thymidine incorporation. This effect was maximal with 100 n M forskolin, occurred after 6–16 h, was reproduced by cyclic AMP-permeable analogues, and was blocked by a protein kinase A inhibitor. Forskolin increased D3 receptor expression up to 135%, but only after 16 h and at concentrations of >1 µ M . Thus, in this cell line, the D3 receptor uses two distinct signaling pathways: it efficiently inhibits adenylyl cyclase and induces mitogenesis, an effect possibly involving tyrosine phosphorylation. Activation of the cyclic AMP cascade potentiates the D3 receptor-mediated mitogenic response, through phosphorylation by a cyclic AMP-dependent kinase of a yet unidentified component. Hence, transduction of the D3 receptor can involve both opposite and synergistic interactions with cyclic AMP.  相似文献   
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We have prepared a monoclonal antibody (MAb), 3D3, raised againstpurified human respiratory mucins. This antibody recognizedmucins and proteolytically derived glycopeptides. The epitoperecognized by the antibody was destroyed by -L-fucosidase, indicatingthat it was present on the carbohydrate moieties. Structuralspecificity was determined by adsorption on a variety of synthetic,insolubilized oligosaccharides. Several lines of evidence indicatethat the 3D3 MAb reacted strongly with the Lewis (Leb) antigen,but also recognized Lea and Ley determinants. This antibodymight be useful to study mucin secretion. human bronchial mucins Lewis b  相似文献   
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