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

The methylation of nuclear and chloroplast DNAs has been examined in relation to the known differential expression of C4 photosynthesis genes in the bundle sheath and mesophyll cells of etiolated, greening, and fully green maize leaves. We have focused our research on phosphoenolpyruvate carboxylase, pyruvate, orthophosphate dikinase, and the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RBUp2Case) which are coded by nuclear genes, and on the large subunit of RBUp2Case which is coded by a plastid gene. Reversed-phase high performance liquid chromatography revealed several kinds of methylated bases in DNAs of both photosynthetic cell types, with the largest amounts in fully green leaves. The occurrence of selective DNA methylation was investigated by employing an isoschizomeric pair of methyl-sensitive and -insensitive endonucleases followed by Southern hybridizations with specific DNA probes. Notably, there was an inverse correlation between the relative abundance of specific transcripts in a given cell type during greening and the methylation status of the corresponding nuclear or chloroplast gene. Furthermore, a heterologous in vitro transcription system using Escherichia coli RNA polymerase revealed that the plastid gene encoding the RBUp2Case large subunit in both cell types was active as a template in the unmethylated state, whereas it was inactive when methylated. Thus, the selective methylation of both chloroplast and nuclear DNA is likely one component of a multilevel control mechanism for the differential regulation of cell-specific C4 photosynthesis gene expression in greening maize leaves.
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PMID:DNA methylation and the differential expression of C4 photosynthesis genes in mesophyll and bundle sheath cells of greening maize leaves. 254 70

We examined evolutionary mechanisms in the tetraploid Elymus caninus by comparing the phylogenetic relationships of 21 accessions suggested by sequence data from two single copy nuclear genes, the largest subunit of RNA polymerase II (RPB2) and phosphoenolpyruvate carboxylase (pepC), and one non-coding chloroplast region, TrnD/T. Elymus caninus is known combining two different genomes, an St genome and an H genome. Data from two single copy nuclear genes showed that there are two versions of the St genome in the species, St1 and St2. Most accessions combined one of these versions with an H genome version but two accessions had both versions of the St sequence for RPB2. This suggests that the RPB2gene may have been duplicated without chromosome doubling, possibly induced by transposable element. Our data also indicate that the H genome sequences in E. caninus have multiple origins, and a close phylogenetic relationship between Hordeum bogdanii and H sequences in some accessions of E. caninus. Thus, it is more likely that H. bogdanii is one of the major donors of the H copy in E. caninus. The maternal origin of E. caninus is the St genome species. There was no correlation between the geographic origin of the accessions and their sequence divergence.
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PMID:Multiple origins of allopolyploid wheatgrass Elymus caninus revealed by RPB2, PepC and TrnD/T genes. 2261 17

To study origin and evolutionary dynamics of tetraploid Elymus trachycaulus that has been cytologically defined as containing StH genomes, thirteen accessions of E. trachycaulus were analyzed using two low-copy nuclear gene Pepc (phosphoenolpyruvate carboxylase) and Rpb2 (the second largest subunit of RNA polymerase II), and one chloroplast region trnL-trnF (spacer between the tRNA Leu (UAA) gene and the tRNA-Phe (GAA) gene). Our chloroplast data indicated that Pseudoroegneria (St genome) was the maternal donor of E. trachycaulus. Rpb2 data indicated that the St genome in E. trachycaulus was originated from either P. strigosa, P. stipifolia, P. spicata or P. geniculate. The Hordeum (H genome)-like sequences of E. trachycaulus are polyphyletic in the Pepc tree, suggesting that the H genome in E. trachycaulus was contributed by multiple sources, whether due to multiple origins or introgression resulting from subsequent hybridization. Failure to recovering St copy of Pepc sequence in most accessions of E. trachycaulus might be caused by genome convergent evolution in allopolyploids. Multiple copies of H-like Pepc sequence from each accession with relative large deletions and insertions might be caused by either instability of Pepc sequence in H- genome or incomplete concerted evolution. Our results highlighted complex evolutionary history of E. trachycaulus.
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PMID:Origin and Reticulate Evolutionary Process of Wheatgrass Elymus trachycaulus (Triticeae: Poaceae). 2594 88