Search results for POLRMT

Showing 9 results out of 9

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Protein (1 results from a total of 1)

Identifier: R-HSA-163267
Species: Homo sapiens
Compartment: mitochondrial matrix
Primary external reference: UniProt: POLRMT: O00411

DNA Sequence (1 results from a total of 1)

Identifier: R-HSA-4686134
Species: Homo sapiens
Compartment: nucleoplasm
Primary external reference: ENSEMBL: ENSG00000099821

Reaction (3 results from a total of 3)

Identifier: R-HSA-1592243
Species: Homo sapiens
Compartment: nucleoplasm, mitochondrial matrix
The POLRMT (mitochondrial RNA polymerase) gene is transcribed in the nucleus to yield mRNA and the mRNA is translated in the cytosol to yield POLRMT precursor, which is then imported into the mitochondria matrix. In the mitochondrial matrix POLRMT transcribes mitochondrial DNA.
Identifier: R-HSA-163296
Species: Homo sapiens
Compartment: mitochondrial matrix
At the beginning of this reaction, 1 molecule of 'POLRMT:TFB2M complex', and 1 molecule of 'TFAM:mitochondrial promoter complex' are present. At the end of this reaction, 1 molecule of 'POLRMT:TFB2M:TFAM:mitochondrial promoter complex' is present.

This reaction takes place in the 'mitochondrial matrix'.
Identifier: R-HSA-6793066
Species: Homo sapiens
Compartment: mitochondrial matrix
TFB1M transfers methyl groups from S-adenosylmethionine to the 6 position of adenosine residues at nucleotides 936 and 937 in 12S mitochondrial rRNA (McCulloch et al. 2002, Seidel-Rogol et al. 2003, Cotney et al. 2009, Guja et al. 2013). The mitochondrial RNA polymerase POLRMT associates directly with TFB1M and increases its methylase activity (Surovtseva and Shadel 2013). Alleles of TFB1M modify the severity of hearing loss associated with the A1555G mutation in 12S rRNA (Bykhovskaya et al. 2004). The A1555G mutation may cause hypermethylation of 12S rRNA which activates AMP kinase, E2F1, and apoptosis (Cotney et al. 2009, Raimundo et al. 2012), however the reported hypermethylation and deafness phenotype have been questioned (Lee et al. 2015). Disruption of Tfb1m in mice is lethal and causes loss of adenine methylation of the 12S RNA (Metodiev et al. 2009).

Complex (1 results from a total of 1)

Identifier: R-HSA-163306
Species: Homo sapiens
Compartment: mitochondrial matrix

Pathway (2 results from a total of 2)

Identifier: R-HSA-163282
Species: Homo sapiens
Human mtDNA is transcribed by a dedicated mitochondrial RNA polymerase (POLRMT), which displays significant sequence similarity to the monomeric RNA polymerases found in bacteriophages. In contrast to the phage T7 RNA polymerase, POLRMT cannot interact with promoter DNA and initiate transcription on its own, but requires the presence of the mitochondrial transcription factor A (TFAM), and either transcription factor B1 (TFB1M) or B2 (TFB2M). The 4 proteins of the basal mitochondrial transcription machinery have been purified in recombinant form and used to reconstitute transcription in vitro with a promoter containing DNA fragment (Falkenberg et al., 2002). Although both TFB1M and TFB2M can support in vitro transcription with POLRMT, TFB2M is at least two orders of magnitude more active than TFB1M and the physiological role of TFB1M in mitochondrial transcription has not yet been completely defined. The TFB1M and TFB2M display primary sequence similarity to a family of rRNA methyltransferases, which dimethylates two adjacent adenosine bases near the 3' end of the small subunit rRNA during ribosome biogenesis (Falkenberg et al., 2002; McCulloch et al., 2002). Human TFB1M is, in fact, a dual function protein, which not only support mitochondrial transcription in vitro, but also acts as a rRNA methyltransferase (Seidel-Rogol et al., 2003). The methyltransferase activity is not required for transcription, since point mutations in conserved methyltransferase motifs of TFB1M revealed that it stimulates transcription in vitro independently of S-adenosylmethionine binding and rRNA methyltransferase activity.
Identifier: R-HSA-74160
Species: Homo sapiens
Gene expression encompasses transcription and translation and the regulation of these processes. RNA Polymerase I Transcription produces the large preribosomal RNA transcript (45S pre-rRNA) that is processed to yield 18S rRNA, 28S rRNA, and 5.8S rRNA, accounting for about half the RNA in a cell. RNA Polymerase II transcription produces messenger RNAs (mRNA) as well as a subset of non-coding RNAs including many small nucleolar RNAs (snRNA) and microRNAs (miRNA). RNA Polymerase III Transcription produces transfer RNAs (tRNA), 5S RNA, 7SL RNA, and U6 snRNA. Transcription from mitochondrial promoters is performed by the mitochondrial RNA polymerase, POLRMT, to yield long transcripts from each DNA strand that are processed to yield 12S rRNA, 16S rRNA, tRNAs, and a few RNAs encoding components of the electron transport chain. Regulation of gene expression can be divided into epigenetic regulation, transcriptional regulation, and post-transcription regulation (comprising translational efficiency and RNA stability). Epigenetic regulation of gene expression is the result of heritable chemical modifications to DNA and DNA-binding proteins such as histones. Epigenetic changes result in altered chromatin complexes that influence transcription. Gene Silencing by RNA mostly occurs post-transcriptionally but can also affect transcription. Small RNAs originating from the genome (miRNAs) or from exogenous RNA (siRNAs) are processed and transferred to the RNA-induced silencing complex (RISC), which interacts with complementary RNA to cause cleavage, translational inhibition, or transcriptional inhibition.

Icon (1 results from a total of 1)

Species: Homo sapiens
Curator: Bruce May
Designer: Cristoffer Sevilla
POLRMT icon
DNA-directed RNA polymerase, mitochondrial
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