HMM Summary Page: TIGR00922

Functiontranscription termination/antitermination factor NusG
Gene SymbolnusG
Trusted Cutoff135.70
Domain Trusted Cutoff135.70
Noise Cutoff125.85
Domain Noise Cutoff125.85
Isology Typeequivalog
HMM Length172
Mainrole CategoryTranscription
Subrole CategoryTranscription factors
Gene Ontology TermGO:0003715: transcription termination factor activity molecular_function
GO:0006353: transcription termination, DNA-dependent biological_process
AuthorHaft DH, Durkin S, Selengut J
Entry DateSep 13 2000 11:49AM
Last ModifiedFeb 14 2011 3:27PM
CommentNusG proteins are transcription factors which are aparrently universal in prokaryotes (archaea and eukaryotes have homologs that may have related functions). The essential components of these factors include an N-terminal RNP-like (ribonucleoprotein) domain and a C-terminal KOW motif (PF00467) believed to be a nucleic acid binding domain [3]. In E. coli, NusA has been shown to interact with RNA polymerase and termination factor Rho. This model covers a wide variety of bacterial species but excludes mycoplasmas which are covered by a separate model (TIGR01956). The function of all of these NusG proteins is likely to be the same at the level of interaction with RNA and other protein factors to affect termination; however different species may utilize NusG towards different processes and in combination with different suites of affector proteins. In E. coli, NusG promotes rho-dependent termination. It is an essential gene. In Streptomyces virginiae and related species, an additional N-terminal sequence is also present and is suggested to play a role in butyrolactone-mediated autoregulation. In Thermotoga maritima, NusG has a long insert, fails to substitute for E. coli NusG (with or without the long insert), is a large 0.7 % of total cellular protein, and has a general, sequence non-specific DNA and RNA binding activity that blocks ethidium staining, yet permits transcription. Archaeal proteins once termed NusG share the KOW domain but are actually a ribosomal protein corresponding to L24p in bacterial and L26e in eukaryotes (TIGR00405).
ReferencesRN [1] RM 20281307 RT Regulation of rho-dependent transcription termination by NusG is specific to the Escherichia coli elongation complex. RA Pasman Z, von Hippel PH RL Biochemistry 2000 May 9;39(18):5573-85 RN [2] RM 96312350 RT A NusG-like protein from Thermotoga maritima binds to DNA and RNA. RN [3] RM PMID: 12198166 RT Crystal structures of transcription factor NusG in light of its nucleic acid- and protein-binding activities. RA Steiner T, Kaiser JT, Marinkovic S, Huber R, Wahl MC. RL EMBO J. 2002 Sep 2;21(17):4641-53.
Genome PropertyGenProp0132: transcription termination - antitermination Nus factors (HMM)
GenProp0799: bacterial core gene set, exactly 1 per genome (HMM)