Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete nucleotide sequence of the Saccharomyces cerevisiae CPT1 gene, a structural gene for the sn-1,2-diacylglycerol cholinephosphotransferase (Hjelmstad, R. H., and Bell, R. M. (1987) J. Biol. Chem. 262, 3909-3917), was determined. The 2,100-nucleotide extent of DNA sequenced contained an open reading frame encoding 407 amino acids interrupted by an intron near its 5'-end. Northern hybridization analysis detected the presence of 1.4- and 1.7-kilobase transcripts corresponding to the CPT1 gene. S1 nuclease mapping experiments indicated that the 1.4-kilobase transcript was initiated 80 nucleotides upstream from the translational start site near a poly(dA-dT) promoter element and established that the predicted intron was removed in vivo. The previously constructed cpt1::LEU2 insertional mutation was shown to involve disruption of the CPT1 open reading frame approximately in the middle; this construct did not support the production of a stable transcript. The CPT1 promoter region contained several elements homologous to the promoter regions of other phospholipid biosynthetic structural genes. A model for the membrane topography of the predicted 46,305-dalton cholinephosphotransferase was constructed on the basis of predictive methods. The presence of seven transmembrane helices and an asymmetric distribution of hydrophilic regions were predicted. Regional protein homologies to the acetylcholine receptor, phosphoglycerate kinase, and several cytidine diphosphate utilizing enzymes suggested a functional asymmetry which precisely correlated with the predicted topological asymmetry.
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PMID:The sn-1,2-diacylglycerol cholinephosphotransferase of Saccharomyces cerevisiae. Nucleotide sequence, transcriptional mapping, and gene product analysis of the CPT1 gene. 215 42

We have analyzed two genetic variants of C2 muscle cells that have reduced levels of binding activity for alpha-bungarotoxin and have found that both synthesize only low levels of the alpha-subunit of the acetylcholine receptor. In both variants the uptake of 22Na in response to carbachol is diminished in proportion to the reduction in toxin-binding activity. In addition, the kinetic and sedimentation properties of the residual toxin-binding activity in both is indistinguishable from that seen in wild-type cells. Immunoblotting experiments on extracts of the variants using subunit-specific antibodies to alpha- and beta-subunits of the acetylcholine receptor demonstrated that the beta-subunit was present, but failed to detect alpha-subunit. In both variants, the amount of alpha-subunit accumulated after a 5-min period of labeling with [35S]methionine was reduced by over 90%, leading to the conclusion that the alpha-subunit is synthesized at greatly reduced rates. Northern blot and S1 nuclease analysis showed no differences between the alpha-subunit mRNA in wild-type and variant cells.
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PMID:Genetic variants of C2 muscle cells that are defective in synthesis of the alpha-subunit of the acetylcholine receptor. 365 54