Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A sucrose density gradient-purified, membrane-bound tobacco mosaic virus (tomato strain L) (TMV-L) RNA polymerase containing endogenous RNA template was efficiently solubilized with sodium taurodeoxycholate. Solubilization resulted in an increase in the synthesis of positive-strand, 6.4-kb genome-length single-stranded RNA (ssRNA) and a decrease in the production of 6.4-kbp double-stranded RNA (dsRNA) to levels close to the limits of detection. The solubilized TMV-L RNA polymerase was purified by chromatography on columns of DEAE-Bio-Gel and High Q. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining showed that purified RNA polymerase preparations consistently contained proteins with molecular masses of 183, 126, 56, 54, and 50 kDa, which were not found in equivalent material from healthy plants. Western blotting showed that the two largest of these proteins are the TMV-L-encoded 183- and 126-kDa replication proteins and that the 56-kDa protein is related to the 54.6-kDa GCD10 protein, the RNA-binding subunit of yeast eIF-3. The 126-, 183-, and 56-kDa proteins were coimmunoaffinity selected by antibodies against the TMV-L 126-kDa protein and by antibodies against the GCD10 protein. Antibody-linked polymerase assays showed that active TMV-L RNA polymerase bound to antibodies against the TMV-L 126-kDa protein and to antibodies against the GCD10 protein. Synthesis of genome-length ssRNA and dsRNA by a template-dependent, membrane-bound RNA polymerase was inhibited by antibodies against the GCD10 protein, and this inhibition was reversed by prior addition of GCD10 protein.
 ...
PMID:The tobacco mosaic virus RNA polymerase complex contains a plant protein related to the RNA-binding subunit of yeast eIF-3. 922 1

Gcd10p and Gcd14p were first identified genetically as repressors of GCN4 mRNA translation in Saccharomyces cerevisiae. Recent findings indicate that Gcd10p and Gcd14p reside in a nuclear complex required for the presence of 1-methyladenosine in tRNAs. Here we show that Gcd14p is an essential protein with predicted binding motifs for S-adenosylmethionine, consistent with a direct function in tRNA methylation. Two different gcd14 mutants exhibit defects in cell growth and accumulate high levels of initiator methionyl-tRNA (tRNAiMet) precursors containing 5' and 3' extensions, suggesting a defect in processing of the primary transcript. Dosage suppressors of gcd10 mutations, encoding tRNAiMet (hcIMT1 to hcIMT4; hc indicates that the gene is carried on a high-copy-number plasmid) or a homologue of human La protein implicated in tRNA 3'-end formation (hcLHP1), also suppressed gcd14 mutations. In fact, the lethality of a GCD14 deletion was suppressed by hcIMT4, indicating that the essential function of Gcd14p is required for biogenesis of tRNAiMet. A mutation in GCD10 or deletion of LHP1 exacerbated the defects in cell growth and expression of mature tRNAiMet in gcd14 mutants, consistent with functional interactions between Gcd14p, Gcd10p, and Lhp1p in vivo. Surprisingly, the amounts of NME1 and RPR1, the RNA components of RNases P and MRP, were substantially lower in gcd14 lhp1::LEU2 double mutants than in the corresponding single mutants, whereas 5S rRNA was present at wild-type levels. Our findings suggest that Gcd14p and Lhp1p cooperate in the maturation of a subset of RNA polymerase III transcripts.
 ...
PMID:GCD14p, a repressor of GCN4 translation, cooperates with Gcd10p and Lhp1p in the maturation of initiator methionyl-tRNA in Saccharomyces cerevisiae. 1033 Jan 57