Roles of mRNA fate modulators Dhh1 and Pat1 in TNRC6-dependent gene silencing recapitulated in yeast.

The CCR4-NOT complex, the major deadenylase in eukaryotes, plays crucial roles in gene expression at the levels of transcription, mRNA decay, and protein degradation. GW182/TNRC6 proteins, which are core components of the microRNA-induced silencing complex in animals, stimulate deadenylation and repress translation via recruitment of the CCR4-NOT complex. Here we ...
report a heterologous experimental system that recapitulates the recruitment of CCR4-NOT complex by TNRC6 in S. cerevisiae. Using this system, we characterize conserved functions of the CCR4-NOT complex. The complex stimulates degradation of mRNA from the 5' end by Xrn1, in a manner independent of both translation and deadenylation. This degradation pathway is probably conserved in miRNA-mediated gene silencing in zebrafish. Furthermore, the mRNA fate modulators Dhh1 and Pat1 redundantly stimulate mRNA decay, but both factors are required for poly(A) tail-independent translation repression by tethered TNRC6A. Our tethering-based reconstitution system reveals that the conserved architecture of Not1/CNOT1 provides a binding surface for TNRC6, thereby connecting microRNA-induced silencing complex to the decapping machinery as well as the translation apparatus.
Mesh Terms:
Animals, Autoantigens, Cell Cycle Proteins, DEAD-box RNA Helicases, Embryo, Nonmammalian, Gene Expression Regulation, Fungal, Polyadenylation, Protein Biosynthesis, RNA Interference, RNA Stability, RNA, Fungal, RNA, Messenger, RNA-Binding Proteins, Ribonucleases, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors, Zebrafish, Zebrafish Proteins
J. Biol. Chem.
Date: Mar. 27, 2015
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