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11.
We have examined the pattern of protein synthesis during wing disc pattern regulation. Although in vivo culture dramatically alters the pattern of abundant protein synthesis in wing discs, only one protein--RG38--changes specifically in response to pattern regulation. This polypeptide, previously identified as being nonuniformly distributed in wing and haltere discs, is synthesized in a graded distribution across the wing disc. During wing disc pattern regulation, it acts as a molecular marker for regeneration of particular wing disc regions. Thus, the rate of RG38 synthesis increases during regeneration (by fragments with initial low levels) with kinetics that parallel those for regeneration as scored by the presence of adult cuticular structures. 相似文献
12.
13.
DNA studies in a family with Duchenne muscular dystrophy and a deletion at Xp21. 总被引:8,自引:7,他引:1 下载免费PDF全文
C R Greenberg J L Hamerton M Nigli K Wrogemann 《American journal of human genetics》1987,41(2):128-137
We have performed Southern blot analysis on a large, four-generation kindred with Duchenne muscular dystrophy (DMD). Probes 754 (DXS 84), pERT87-1, pERT87-8, pERT87-15 (DXS164), and pXJ-1.1 did not hybridize to digested genomic DNA of affected males. Obligate-carrier mothers and unaffected brothers showed signals of a single X-chromosome copy intensity, and suspected noncarrier sisters demonstrated either a single band of two-copy intensity or informative polymorphisms. Uniform hybridization was seen with probes C7 (DXS28) and D2 (DXS43), which map distal to the DMD locus, and with OTC, which maps proximally. This deletion was present in six affected individuals and has been transmitted through 3 generations to date. On high-resolution chromosome analysis, a deletion within band Xp21 was consistently observed in one affected male studied and in one of the two X chromosomes in obligate carriers. This large molecular and cytogenetically visible deletion in affected DMD individuals without glycerol kinase deficiency, chronic granulomatous disease, retinitis pigmentosa (RP), or ornithine transcarbamylase deficiency is a very rare finding and should prove useful in specifically cloning additional probes within and flanking the DMD locus. 相似文献
14.
Glutathione S-transferases in human prostate 总被引:4,自引:0,他引:4
K D Tew M L Clapper R E Greenberg J L Weese S J Hoffman T M Smith 《Biochimica et biophysica acta》1987,926(1):8-15
A number of human prostatic tissue biopsies have been analyzed for glutathione S-transferase activity, using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. Samples from nine patients (age range 61-90) with benign prostatic hypertrophy who had received no prior chemotherapy had a mean glutathione S-transferase activity of 137 +/- 44 nmol/min per mg with a range of 97-237. A qualitative comparison of the glutathione S-transferase of normal prostate and benign prostatic hypertrophy samples was carried out. Approximately 260-fold purification was achieved using glutathione-Sepharose affinity chromatography, with glutathione S-transferase accounting for approximately 0.19-0.33% of the total protein. Substrate specificity determinations suggested similar, but not identical, glutathione S-transferase subunits in normal prostate and benign prostatic hypertrophy. One- and two-dimensional electrophoresis (isoelectric focusing and 12.5% SDS-polyacrylamide gel electrophoresis) identified at least seven stained polypeptides in the purified glutathione S-transferase preparations. These ranged in Mr from approximately 24,000 to 28,500 and in pI from near neutral to basic. Western blot analysis using polyclonal antibodies raised against rat liver glutathione S-transferase suggested crossreactivity with five of the human isoenzymes in both normal prostate and benign prostatic hypertrophy. One of the glutathione S-transferases, present in both normal prostate and benign prostatic hypertrophy, had an Mr of approx. 24,000 and a near-neutral pI and crossreacted immunologically with a polyclonal antibody raised against human placental glutathione S-transferase (Yf, subunit 7 or pi). These data suggest that four glutathione S-transferases are expressed in human prostate, with subunits from each of the major classes alpha, mu and pi. These are characterized as Ya, Yb, Yb' and Yf (analogous alternative nomenclature subunits 1, 3, 4 and 7). 相似文献
15.
A Mary K E Achyuthan C S Greenberg 《Biochemical and biophysical research communications》1987,147(2):608-614
The binding sites in fibrinogen for Factor XIII were localized using an immunoblotting technique. Platelet Factor XIII bound to fibrinogen and to plasmin degradation products of fibrin(ogen) including Fragments: X, D1-D3, and D-dimer, but did not bind to Fragment E. Binding of Platelet Factor XIII was independent of calcium ions but could be inhibited by the presence of 0.5 M NaCl. Binding could also be inhibited by preincubating Factor XIII with a 100-fold molar excess of fibrinogen but not by 100-fold molar excess of Fragment E. Binding of Factor XIII to fibrinogen was specific, since several other proteins tested (ovalbumin, bovine serum albumin, alpha 2-macroglobulin, beta-galactosidase, fructose kinase, lactic dehydrogenase, triose phosphate isomerase, fumarase and pyruvate kinase) did not bind Factor XIII. Furthermore, binding was not observed either when Factor XIII was left out or when antiFactor XIII antiserum was substituted with nonimmune serum. When fibrinogen was reduced prior to electrophoresis, Factor XIII bound to the A alpha and B beta chains of fibrinogen and des A,B fibrinogen, the B beta-chain of Fragment X, but not the gamma-chains. Localization of the Factor XIII binding sites to the carboxy terminal segments of the A alpha and B beta chains in the Fragment D-domain of fibrinogen could have important physiological consequences. 相似文献
16.
17.
Komandoor E. Achyuthan Ann Mary Robin Bhaermani Charles S. Greenberg 《Molecular and cellular biochemistry》1989,85(1):57-65
Calcium ions are crucial for expression of transglutaminase activity. Although lanthanides have been reported to substitute for calcium in a variety of protein functions, they did not replace the calcium requirement during transglutaminase activity measurements. Furthermore, lanthanides strongly inhibited purified liver transglutaminase activity using either casein or fibrinogen as substrates. Terbium (III) inhibition of transglutaminase-catalyzed putrescine incorporation into casein was not reversed by the presence of 10–200 fold molar excess of calcium ions (Ki for Tb(III)=60 µM). Conformational changes in purified liver transglutaminase upon Tb(III) binding were evident from a biphasic effect of Tb(III) on transglutaminase binding to fibrin. Low concentrations of Tb(III) (1 µM to 10 µM inhibited the binding of transglutaminase to fibrin, whereas higher concentrations (20 µM to 100 µM promoted binding. Conformational changes in purified liver transglutaminase consequent to Tb(III) binding were also demonstrated by fluorescence spectroscopy due to Forster energy transfer. Fluorescence emission was stable to the presence of 200 mM NaCl and 100 mM CaCl2 only partially quenched emission. Purified liver transglutaminase strongly bound to Tb(III)-Chelating Sepharose beads and binding could not be disrupted by 100 mM CaCl2 solution. Our data suggest that Tb(III)-induced conformational changes in transglutaminase are responsible for the observed effects on enzyme structure and function. The potential applications of Tb(III)-transglutaminase interactions in elucidating the structure-function relationships of liver transglutaminase are discussed. 相似文献
18.
Polyethylene glycol-modified urate oxidase (PEG-uricase) holds promise as a hypouricemic agent for treating gout and as an adjunct to cytolytic therapy of hematologic malignancies. Spectrophotometric assays of urate oxidase are not sensitive enough for pharmacokinetic evaluation of PEG-uricase in clinical trials. We have therefore developed a more sensitive radiochemical-HPLC assay for urate oxidase activity in untreated plasma, in which 14C in urate and in the reaction product, allantoin, is monitored in the uv detector effluent with a flow-through scintillation counter. The assay is linear with amount of enzyme and time of incubation and can detect less than 1 x 10(-5) U/ml uricase in plasma. The assay accounts for plasma samples of widely differing urate content. 相似文献
19.
Soluble derivatives of the beta amyloid protein precursor of Alzheimer's disease are labeled by antisera to the beta amyloid protein 总被引:6,自引:0,他引:6
M R Palmert S L Siedlak M B Podlisny B Greenberg E R Shelton H W Chan M Usiak D J Selkoe G Perry S G Younkin 《Biochemical and biophysical research communications》1989,165(1):182-188
The amyloid deposited in Alzheimer's disease (AD) is composed primarily of a 39-42 residue polypeptide (beta AP) that is derived from a larger beta amyloid protein precursor (beta APP). In previous studies, we and others identified full-length, membrane-associated forms of the beta APP and showed that these forms are processed into soluble derivatives that lack the carboxyl-terminus of the full-length forms. In this report, we demonstrate that the soluble approximately 125 and approximately 105 kDa forms of the beta APP found in human cerebrospinal fluid are specifically labeled by several different antisera to the beta AP. This finding indicates that both soluble derivatives contain all or part of the beta AP sequence, and it suggests that one or both of these forms may be the immediate precursor of the amyloid deposited in AD. 相似文献
20.
Overproduction of peroxide-scavenging enzymes in Escherichia coli suppresses spontaneous mutagenesis and sensitivity to redox-cycling agents in oxyR-mutants. 总被引:20,自引:0,他引:20 下载免费PDF全文
Mutations that suppressed the H2O2 sensitivity of Escherichia coli oxyR- strains caused elevated levels of one three enzymes that destroy organic and hydrogen peroxides: catalase-hydroperoxidase I (the katG gene product), catalase-hydroperoxidase II (controlled by katEF) or alkyl hydroperoxide reductase (specified by the ahp genes). The continuous high-level expression of any one of these enzymes also conferred resistance in an oxyR deletion mutant against other compounds such as N-ethylmaleimide and the superoxide-generator menadione. Overproduction of alkyl hydroperoxide reductase, but not of the catalases, gave resistance to the organic oxidant cumene hydroperoxide. The E. coli delta oxyR strains also exhibited a strongly elevated frequency of spontaneous mutagenesis, as reported for such mutants in Salmonella typhimurium. This mutagenesis was greatly diminished by the individual overexpression of these scavenging enzymes. All of these phenotypes--enzyme overproduction, resistance to oxidants and suppression of spontaneous mutagenesis--remained linked upon transduction of the mutant katG or ahp genes. Peroxides thus appear to mediate the toxicity of a variety of redox agents, and are produced in sufficient quantity during normal metabolism to cause a substantial increase in 'spontaneous' mutations in cells that lack adequate antioxidant defenses. 相似文献