Project description:Gene expression involving RNA polymerase II is regulated by the concerted interplay between mRNA synthesis and degradation, a crosstalk where mRNA decay machinery impacts transcription and transcription machinery influences mRNA stability. Rpb4, and likely the dimer Rpb4/7 seem to be the central components of the RNA pol II governing these processes. In this work we unravel more precisely the molecular mechanisms participated by Rpb4 that mediates the posttranscriptional events regulating mRNA imprinting and stability. We analysed genome-wide, by RIP-seq, the association of Rpb4 with mRNAs and demonstrated that it targets a broad population of about 1400 transcripts. A group of mRNAs are also targets of the RPB, Puf3. We demonstrated that Rpb4 and Puf3, physically, genetically and functionally interact and cooperate to imprint and regulate stability of this group of mRNA. We also demonstrated, by the first time, that Puf3 associates with the chromatin, in an Rpb4-dependent manner. Our data also point to Rpb4 as the key element of the RNA pol II that interplay mRNA synthesis, imprinting and stability, in cooperation with RBPs.
Project description:Gene expression involving RNA polymerase II is regulated by the concerted interplay between mRNA synthesis and degradation, a crosstalk where mRNA decay machinery impacts transcription and transcription machinery influences mRNA stability. Rpb4, and likely the dimer Rpb4/7 seem to be the central components of the RNA pol II governing these processes. Here we investigate the effect of ∆rrp4 on the potential chromatin association of the RNA binding protein Puf3 to chromatin in S. cerevisiae.
Project description:Puf3 is a RNA-binding protein, a member of the conserved Puf-protein family. Combining different functional genomics data, we have analyzed the role of Puf3 in post-transcriptional gene regulation in S. pombe. We present data on Puf3 interacting proteins and regulatory mRNA targets.
Project description:Affinity purification of S. cerevisiae or N. crassa Puf3 from S. cerevisiae cells and identification of associated RNAs by microarray
Project description:Pbp1 (polyA-binding protein - binding protein 1) is a stress granule marker and polyglutamine expansions in its mammalian ortholog ataxin-2 have been linked to neurodegenerative conditions. Pbp1 was recently shown to form intracellular assemblies that function in the negative regulation of TORC1 signaling under respiratory conditions. Furthermore, it was observed that loss of Pbp1 leads to mitochondrial dysfunction. Here, we show that loss of Pbp1 leads to a specific decrease in mitochondrial proteins whose encoding mRNAs are targets of the RNA-binding protein Puf3, suggesting a functional relationship between Pbp1 and Puf3. We found that Pbp1 stabilizes and promotes the translation of Puf3-target mRNAs in respiratory conditions, such as those involved in the assembly of cytochrome c oxidase. We further show that Pbp1 and Puf3 associate through their respective low complexity domains, which is required for target mRNA stabilization and translation. Our findings reveal a key role for Pbp1-containing assemblies in enabling the translation of mRNAs critical for mitochondrial biogenesis and respiration under metabolically challenging conditions. They may further explain prior associations of Pbp1/ataxin-2 with stress granule biology and RNA metabolism.
Project description:Cells expressing Tap-Tagged PUF3 were used for selection on IgG beads, then released using TEV protease. Samples were input and bound fraction without rRNA removal, and unbound fraction and input after rRNA removal with oligonucleotides and RNase H.
Project description:The Puf family of RNA-binding proteins regulate gene expression by controlling protein synthesis or stimulating RNA decay. Puf3p is one of six related proteins in Saccharomyces cerevisiae characterised as targeting and regulating decay of nuclear-encoded mRNAs specifying mitochondrial proteins. Much prior work has examined how Puf3p regulates COX17 mRNA. We undertook a genome-wide approach to quantitatively assess the impact of loss of PUF3 on gene expression. Comparing transcript levels in wild-type and puf3∆ cells revealed that that only a small fraction of mRNA levels alter, suggesting Puf3p determines mRNA stability for only some target mRNAs.