This is the N-terminal domain of transcription termination/antitermination protein NusG, which is involved in transcription elongation, termination and antitermination. It also occurs at the N-terminal of transcription antitermination protein RfaH and in the transcription elongation factor Spt5 [ (PUBMED:19000817) ].
GO process:
regulation of transcription, DNA-templated (GO:0006355)
Family alignment:
There are 19669 NGN domains in 19664 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing NGN domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with NGN domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing NGN domain in the selected taxonomic class.
Novel domains and orthologues of eukaryotic transcription elongation factors.
Nucleic Acids Res. 2002; 30: 3643-52
Display abstract
The passage of RNA polymerase II across eukaryotic genes is impeded by the nucleosome, an octamer of histones H2A, H2B, H3 and H4 dimers. More than a dozen factors in the yeast Saccharomyces cerevisiae are known to facilitate transcription elongation through chromatin. In order to better understand the evolution and function of these factors, their sequences have been compared with known protein, EST and DNA sequences. Elongator subcomplex components Elp4p and Elp6p are shown to be homologues of ATPases, yet with substitutions of amino acids critical for ATP hydrolysis, and novel orthologues of Elp5p are detectable in human, and other animal, sequences. The yeast CP complex is shown to contain a likely inactive homologue of M24 family metalloproteases in Spt16p/Cdc68p and a 2-fold repeat in Pob3p, the orthologue of mammalian SSRP1. Archaeal DNA-directed RNA polymerase subunit E" is shown to be the orthologue of eukaryotic Spt4p, and Spt5p and prokaryotic NusG are shown to contain a novel 'NGN' domain. Spt6p is found to contain a domain homologous to the YqgF family of RNases, although this domain may also lack catalytic activity. These findings imply that much of the transcription elongation machinery of eukaryotes has been acquired subsequent to their divergence from prokaryotes.
The bacterial transcription antiterminator RfaH has been shown to act, in a purified biochemical system, by binding both RNA polymerase and the nontemplate strand of DNA at the regulatory site ops.
Structure and function of the human transcription elongation factor DSIF.
J Biol Chem. 1999; 274: 8085-92
Display abstract
5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) is a classic inhibitor of transcription elongation by RNA polymerase II (pol II). We have previously identified and purified a novel transcription elongation factor, termed DSIF (for DRB sensitivity-inducing factor), that makes transcription sensitive to DRB. DSIF is composed of 160- and 14-kDa subunits, which are homologs of the Saccharomyces cerevisiae transcription factors Spt5 and Spt4. DSIF may either repress or stimulate transcription in vitro, depending on conditions, but its physiological function remains elusive. Here we characterize the structure and function of DSIF p160. p160 is shown to be a ubiquitous nuclear protein that forms a stable complex with p14 and interacts directly with the pol II largest subunit. Mutation analysis of p160 is used to identify structural features essential for its in vitro activity and to map the domains required for its interaction with p14 and pol II. Finally, a p160 mutant that represses DSIF activity in a dominant-negative manner is identified and used to demonstrate that DSIF represses transcription from various promoters in vivo.
