biostudies-literatureJia HNIGMS NIH HHS7292-7https://www.ebi.ac.uk/biostudies/studies/S-EPMC3358879biostudies-literatureUnknown109(19)Many RNA-processing events in the cell nucleus involve the Trf4/Air2/Mtr4 polyadenylation (TRAMP) complex, which contains the poly(A) polymerase Trf4p, the Zn-knuckle protein Air2p, and the RNA helicase Mtr4p. TRAMP polyadenylates RNAs designated for processing by the nuclear exosome. In addition, TRAMP functions as an exosome cofactor during RNA degradation, and it has been speculated that this role involves disruption of RNA secondary structure. However, it is unknown whether TRAMP displays RNA unwinding activity. It is also not clear how unwinding would be coordinated with polyadenylation and the function of the RNA helicase Mtr4p in modulating poly(A) addition. Here, we show that TRAMP robustly unwinds RNA duplexes. The unwinding activity of Mtr4p is significantly stimulated by Trf4p/AProceedings of the National Academy of Sciences of the United States of AmericaRNA unwinding by the Trf4/Air2/Mtr4 polyadenylation (TRAMP) complex.PMC3358879GM067700R01 GM067700R01 GM069949GM069949Anderson JTJia HJankowsky EWang XfalseRNA unwinding by the Trf4/Air2/Mtr4 polyadenylation (TRAMP) complex.Many RNA-processing events in the cell nucleus involve the Trf4/Air2/Mtr4 polyadenylation (TRAMP) complex, which contains the poly(A) polymerase Trf4p, the Zn-knuckle protein Air2p, and the RNA helicase Mtr4p. TRAMP polyadenylates RNAs designated for processing by the nuclear exosome. In addition, TRAMP functions as an exosome cofactor during RNA degradation, and it has been speculated that this role involves disruption of RNA secondary structure. However, it is unknown whether TRAMP displays RNA unwinding activity. It is also not clear how unwinding would be coordinated with polyadenylation and the function of the RNA helicase Mtr4p in modulating poly(A) addition. Here, we show that TRAMP robustly unwinds RNA duplexes. The unwinding activity of Mtr4p is significantly stimulated by Trf4p/A2012-01-01T00:00:00Z2012 May2025-04-04T14:32:11.923Z2019-03-27T00:53:46ZS-EPMC33588792253266610.1073/pnas.1201085109