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)

The gene for ATPase subunit 9 of yeast mitochondria (Oli 1) contains two promoter sequences (Op1 and Op2) separated by 78 nucleotides. Both promoters are transcribed in vivo and in vitro though with different efficiency. The upstream promoter (Op1) is 12-15 times stronger than the downstream promoter (Op2), and this difference in promoter activity is partly attributable to the influence of the +2 nucleotide (Biswas, T. K., and Getz, G. S. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 270-274). In addition, the presence of the strong promoter (Op1) in close proximity to the weak promoter (Op2) partially inhibits the expression of the latter (Op2). The relative orientation of the two promoters has no influence on these inhibitory effects. When both promoters are present in the same reaction mixture, the strong promoter always competes effectively with the weak promoter for limited RNA polymerase (trans or competition effect). When the two promoters are present in the same plasmid, there is an inhibitory interaction between them that decreases as the distance between the two promoters increases (cis or position effect). Thus, the difference between the activities of a strong and a weak mitochondrial promoter in tandem is a function of two effects, the trans or competition effect and the cis or position-related effect. A model for promoter-promoter interactions is proposed.
 ...
PMID:Promoter-promoter interactions influencing transcription of the yeast mitochondrial gene, Oli 1, coding for ATPase subunit 9. Cis and trans effects. 296 50

We have determined transcriptional initiation sites for the ATPase subunit 9 gene on the yeast mitochondrial genome. Using S1 nuclease mapping, in vitro capping of primary transcripts with GTP and guanylyl transferase, and in vitro transcription analysis with purified mitochondrial RNA polymerase, we find the major site of transcriptional initiation to be at a point 630 nucleotides upstream of the coding region for the gene. In addition, we find much lower levels of initiation at a second site 78 nucleotides downstream of the first. Both initiation sites occur at the same position within a nonanucleotide sequence which we have previously found associated with initiation of rRNA synthesis. This work further supports the notion that this nonanucleotide sequence is an integral component of mitochondrial promoters and indicates that the same RNA polymerase is used for transcription of both mRNA and rRNA in yeast mitochondria.
 ...
PMID:Initiation of transcription of the yeast mitochondrial gene coding for ATPase subunit 9. 623 27

We have identified the barley gene and cDNA encoding the plastid phage-type RNA polymerase (RNAP), nuclear-encoded plastid RNAP (RpoTp), and the nearly full-length cDNA of the mitochondrial RNAP, nuclear-encoded mitochondrial RNAP (RpoTm). RpoTp spans more than 9000 nt, consists of 19 exons and 18 introns, gives rise to a 3632-nt mRNA and is localized to the long arm of chromosome 1 (7H). The length of the deduced polypeptide is 948 residues. The mRNA levels of RpoTp and RpoTm were determined in roots and primary leaf sections of 7-day-old barley seedlings of the albostrians mutant, which were either phenotypically normal and exhibited a gradient of chloroplast development, or contained ribosome-deficient undifferentiated plastids. Transcript levels of RpoTp and RpoTm in almost all sections reached higher concentrations in plastid ribosome-deficient leaves than in the wild-type material, except in the most basal part of the leaf. These data indicate a role of plastid-to-nucleus signalling in the expression of the two RpoT genes. The mRNA levels of the plastid genes, beta-subunit of plastid-encoded RNAP (rpoB), proteolytic subunit of the Clp protease (clpP) and ribosomal protein Rpl2 (rpl2), all known to be transcribed by the nuclear-encoded RNAP (NEP), followed closely the pattern of RpoTp mRNA accumulation, strongly suggesting that RpoTp and NEP are identical. Transcripts of RpoTm and RpoTm-transcribed mitochondrial genes cytochrome oxidase subunit 2 (coxII) and ATPase subunit 9 (atp9) accumulated to the highest levels in the most basal parts of the leaf and declined considerably towards the leaf tip with a pronounced reduction in green versus white leaves. Our data revealed a marked influence of the developmental stage of the plastid on the expression and activity of organellar phage-type RNAPs and their target genes. Thus, interorganellar cross-talk in the regulated expression of nuclear-encoded plastid and mitochondrial RNAP genes might be a key element governing the concerted expression of genes located within plastids, mitochondria and the nucleus of the plant cell.
 ...
PMID:Chloroplast development affects expression of phage-type RNA polymerases in barley leaves. 1508 95