TRAMP complex

TRAMP complex (Trf4/Air2/Mtr4p Polyadenylation complex) is a multiprotein, heterotrimeric complex having distributive polyadenylation activity and identifies wide varieties of RNAs produced by polymerases. It was originally discovered in Saccharomyces cerevisiae by LaCava et al., Vanacova et al. and Wyers et al. in 2005. The analogous complex in humans is sometimes referred to as the TRAMP-like complex (see ). (Mtr4/Dob1), a poly(A) polymerase (either Trf4 or Trf5) and a zinc knuckle protein (either Air1 or Air2).The interaction between the exosomes (Rrp6p/Rrp47p) and Mtr4p of TRAMP complex helps in RNA surveillance and degradation of abnormal RNAs It interacts with the exosome complex in the nucleus of eukaryotic cells and is involved in the 3' end processing and degradation of ribosomal RNA and snoRNAs. The TRAMP complex trims the poly(A) tails of RNAs destined for Rrp6 and the core exosome down to 4-5 adenosines assisting in transcript recognition and exosome complex activation. The substrate specificity of exosomes is improved in the presence of TRAMP complex as it acts as a crucial cofactor and helps in maintaining various activities.…

TRAMP complex (Trf4/Air2/Mtr4p Polyadenylation complex) is a multiprotein, heterotrimeric complex having distributive polyadenylation activity and identifies wide varieties of RNAs produced by polymerases. It was originally discovered in Saccharomyces cerevisiae by LaCava et al., Vanacova et al. and Wyers et al. in 2005. The analogous complex in humans is sometimes referred to as the TRAMP-like complex (see ). (Mtr4/Dob1), a poly(A) polymerase (either Trf4 or Trf5) and a zinc knuckle protein (either Air1 or Air2).The interaction between the exosomes (Rrp6p/Rrp47p) and Mtr4p of TRAMP complex helps in RNA surveillance and degradation of abnormal RNAs]] It interacts with the exosome complex in the nucleus of eukaryotic cells and is involved in the 3' end processing and degradation of ribosomal RNA and snoRNAs. The TRAMP complex trims the poly(A) tails of RNAs destined for Rrp6 and the core exosome down to 4-5 adenosines assisting in transcript recognition and exosome complex activation. The substrate specificity of exosomes is improved in the presence of TRAMP complex as it acts as a crucial cofactor and helps in maintaining various activities. In this way, TRAMP plays a critical role in ridding the cell of noncoding transcripts generated through pervasive RNA polymerase II transcription, as well as functioning in the biogenesis and turnover of functional coding and noncoding RNAs. TRAMP complex also affects various other RNA processes either directly or indirectly. It is involved in RNA export, Splicing, hetero-chromatic gene silencing and helps in maintaining stability of genome. The Ski2 like helicase Mtr4p was discovered during the screening of heat resistant mutants that gather Poly(A) RNA in the nucleus and is mainly involved in unwinding activity. Mtr4p (also called as Dob1p) is an SF2 helicase and belongs to DExH-box RNA helicases family consisting of two RecA like domains. It also consists of WH domain (Winged Helix domain), an Arch domain (also called as stalk and KOW domain [Kyprides, Ouzounis, Woese domain]) and helical bundle domain. The packing of the WH and helical bundle domains on surface of the helicase core results in the formation of a channel for ssRNA. Mtr4p requires ATP or dATP hydrolysis for RNA duplex unwinding mediated by Q-motif. A single-stranded region 3' to the paired region is also essential for the unwinding activity of Mtr4p. Through direct contact with various components of exosome, Mtr4p helps in proper addition of RNA substrates of TRAMP complex to nuclear exosome. ==References==

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