The domain within your query sequence starts at position 1 and ends at position 127; the E-value for the RPOL4c domain shown below is 9.32e-62.

MEVKDANAALLSNYEVFQLLTDLKEQRKESGKNKHSAGQQNLNAITYETLKYISKTPCRN
QSPAIVQEFLTAMKSHKLTKAEKLQLLNHRPMTAVEIQLMVEESEERLTEEQIEALLHTV
TSILPAG

RPOL4c

DNA-directed RNA-polymerase II subunit
RPOL4c
SMART accession number:SM00657
Description: -
Interpro abstract (IPR006590):

DNA-directed RNA polymerases EC 2.7.7.6 (also known as DNA-dependent RNA polymerases) are responsible for the polymerisation of ribonucleotides into a sequence complementary to the template DNA. In eukaryotes, there are three different forms of DNA-directed RNA polymerases transcribing different sets of genes. Most RNA polymerases are multimeric enzymes and are composed of a variable number of subunits. The core RNA polymerase complex consists of five subunits (two alpha, one beta, one beta-prime and one omega) and is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme [ (PUBMED:3052291) ]. The core RNA polymerase complex forms a "crab claw"-like structure with an internal channel running along the full length [ (PUBMED:10499798) ]. The key functional sites of the enzyme, as defined by mutational and cross-linking analysis, are located on the inner wall of this channel.

RNA synthesis follows after the attachment of RNA polymerase to a specific site, the promoter, on the template DNA strand. The RNA synthesis process continues until a termination sequence is reached. The RNA product, which is synthesised in the 5' to 3' direction, is known as the primary transcript.

Eukaryotic nuclei contain three distinct types of RNA polymerases that differ in the RNA they synthesise:

  • RNA polymerase I: located in the nucleoli, synthesises precursors of most ribosomal RNAs.
  • RNA polymerase II: occurs in the nucleoplasm, synthesises mRNA precursors.
  • RNA polymerase III: also occurs in the nucleoplasm, synthesises the precursors of 5S ribosomal RNA, the tRNAs, and a variety of other small nuclear and cytosolic RNAs.

Eukaryotic cells are also known to contain separate mitochondrial and chloroplast RNA polymerases. Eukaryotic RNA polymerases, whose molecular masses vary in size from 500 to 700kDa, contain two non-identical large (>100kDa) subunits and an array of up to 12 different small (less than 50kDa) subunits.

A major role in the regulation of eukaryotic protein-coding genes is played by the gene-specific transcriptional regulators, which recruit the RNA polymerase II holoenzyme to the specific promoter. The Rpb4 and Rpb7 subunits of yeast RNA polymerase II form a heterodimeric complex essential for promoter-directed transcription initiation. The Rpb4-Rpb7 complex is not required for stable recruitment of polymerase to active preinitiation complexes, suggesting that Rpb4-Rpb7 mediates an essential step subsequent to promoter binding [ (PUBMED:11087726) ].

This entry represents a domain present in DNA-directed RNA polymerase II subunit Rpb4 and DNA-directed RNA polymerase III subunit RPC9.

Family alignment:
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There are 2233 RPOL4c domains in 2231 proteins in SMART's nrdb database.

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