Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chinese hamster ovary (CHO) cells cluster in the presence of pertussis toxin, a response that is correlated with the ADP-ribosylation of a Mr = 41,000 membrane protein by the toxin. A ricin-resistant line of CHO cells (CHO-15B) which specifically lacks the terminal NeuAc----Gal beta 4GlcNAc oligosaccharide sequence on glycoproteins did not cluster in response to pertussis toxin. These cells do contain the Mr = 41,000 protein substrate for the enzymatic activity of the toxin which suggests that pertussis toxin, like certain plant lectins, does not bind to or is not internalized by the CHO-15B cells. There was no evidence of pertussis toxin binding to gangliosides or neutral glycolipids isolated from CHO cells but the toxin bound to a Mr = 165,000 component in N-octyglucoside extracts of CHO cells that had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroblotted to nitrocellulose. Plant lectins from Ricinus communis and Erythina cristagalli detected a similar size band in CHO cells and also did not react with CHO-15B cells. Unlike pertussis toxin, these plant lectins recognized two other major bands in CHO cell extracts and reacted best after sialidase treatment of nitrocellulose transfers containing CHO cell extracts. Conversely, sialidase treatment abolished binding a pertussis toxin and wheat germ agglutinin, a plant lectin that reacts with multivalent sialic acid residues on glycoproteins, to the Mr = 165,000 band. Purified B oligomer of pertussis toxin also uniquely detected a Mr = 165,000 component in CHO cell extracts while the A subunit of pertussis toxin was unreactive. These results indicate that pertussis toxin binds to a CHO cell glycoprotein with N-linked oligosaccharides and that sialic acid contributes to the complementary receptor site for the toxin. In addition, they suggest that a glycoprotein may serve as a cell surface receptor for pertussis toxin and that this interaction is mediated by a lectin-like binding site located on the B oligomer.
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PMID:Lectin-like binding of pertussis toxin to a 165-kilodalton Chinese hamster ovary cell glycoprotein. 335 Aug 15

Leaf sheath color plays an important role as a marker for rice genetic improvement. A recombinant inbred line (RIL) population consisting of 220 individuals was developed from a cross between an Oryza sativa subsp. indica variety, IRBB60, and an Oryza sativa subsp. japonica variety, 9407. Within the RIL population, a line, RI51, was found to have purple leaf sheath (PSH). To map the gene governing PSH, RI51 was crossed with 9407 green leaf sheath (GSH) to develop an F2 segregating population. The distribution of F2 plants with PSH and GSH fitted a segregation ratio of 3:1, indicating that the PSH was controlled by a major dominant gene. The gene locus for PSH, tentatively designated as PSH1(t), was identified by surveying two bulks made of the respective 40 individuals with PSH and GSH with SSR markers covering the entire rice genome. The survey indicated that the PSH1(t) region was located on chromosome 1. Further confirmation was made using a large random sample of 360 individuals from the same F2 population and the PSH1(t) locus was then mapped on chromosome 1 between SSR markers RM3475 and RM7202 with genetic distances of 2.0 and 1.1 cM, respectively. For fine mapping of PSH1(t), a large F(2:3) segregating population with 3300 individuals from the seven heterozygous F2 plants in the RM3475-RM7202 region was constructed. Analysis of recombinants in the PSH1(t) region anchored the gene locus to an interval of 23.5 kb flanked by the left marker L03 and the right marker L05. Sequence analysis of this fragment predicted six open reading frames encoding a putative trans-sialidase, a putative Plastidic ATP/ADP-transporter, and four unknown proteins. The detailed genetic and physical maps of the PSH1(t) locus will be very useful in molecular cloning of the PSH1(t) gene.
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PMID:Delimitation of the PSH1(t) gene for rice purple leaf sheath to a 23.5 kb DNA fragment. 1923 55