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Scutenaire, J.

Publications and source records attributed to Scutenaire, J..

3 recordsLinked to original sources

Pho92 direct interaction with Not1 recruits the CCR4-NOT complex to m6A containing mRNAs to modulate meiosis in S. cerevisiae

N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic mRNAs. In S. cerevisiae, m6A is exclusively deposited during meiosis, where it plays an essential role in meiotic progression. In this context, the absence of Pho92, the sole known m6A-binding protein in budding yeast, leads to the abnormal persistence of m6A-containing mRNAs, ultimately resulting in delayed meiosis. Here, we investigate how m6A recognition by Pho92 regulates gene expression. Using complementary in vivo and in vitro approaches, we identify direct interactions between Pho92 and Not1, the scaffold subunit of the CCR4-NOT deadenylase complex. Structural analyses reveal that a short evolutionarily conserved motif in Pho92 adopts an -helical conformation that docks onto specific regions of Not1. Functionally, these interactions are required for efficient meiotic progression. Altogether, our findings demonstrate that Pho92 couples m6A recognition to the main deadenylase to shape the meiotic transcriptome. More broadly, our work provides mechanistic insights into how epitranscriptomic signals interface with the core mRNA decay machinery to regulate gene expression during cellular differentiation.

molecular biology↗

RBProximity-CLIP Enables Subcellular Mapping of RNA-Binding Protein Interactions at Nucleotide Resolution

RNA-binding proteins (RBPs) enable post-transcriptional gene regulation (PTGR) through specific interactions with RNA molecules, influencing processes ranging from nuclear processing and export to cytoplasmic localization, translation, storage and degradation. A key determinant of PTGR processes is the subcellular compartmentalization of RBPs, which dictates RNA targets they can access and the regulation performed in that environment. To characterize RBP-RNA interactions at subcellular resolution, we developed RBProximity-CLIP. RBProximity-CLIP enables compartment-specific isolation and profiling of individual RBP-RNA interactions by combining APEX2-based proximity labeling and 4-thiouridine-enhanced RNA-protein crosslinking, with sequential RBP- and biotin-affinity purifications. Using this approach, we profiled the RNA targets of three RBPs, AGO2, YBX1, and ELAVL1, across the cytoplasmic, nuclear, and nucleolar compartments, revealing nucleus-specific miRNA-mediated AGO2 targets, as well as subsets of YBX1 and ELAVL1 targets that differ by compartment, yet share identical binding motifs. RBProximity-CLIP enables specific and sensitive detection of compartment-specific RBP-RNA interactomes, thereby providing new insight into spatial gene regulation by RBPs.

cell biology↗

The S. cerevisiae m6A-reader Pho92 impacts meiotic recombination by controlling key methylated transcripts

N6-methyladenosine (m6A), the most abundant internal modification of eukaryotic mRNAs, participates in the post-transcriptional control of gene expression. In Saccharomyces cerevisiae, m6A is only found during meiosis. Although the deletion of the m6A- methyltransferase Ime4 impairs this process, the molecular impact of m6A on gene expression remains ill defined. Here we investigated the function of the budding yeast m6A reader Pho92. We found that Pho92 is specifically expressed during meiosis and impacts meiotic progression. We used high-throughput RNA sequencing and mapping of Pho92-binding sites following UV-crosslinking to show that Pho92 is recruited to specific mRNAs in an m6A-dependent manner during the meiotic prophase, preceding their down-regulation. Strikingly, point mutations altering m6A sites in mRNAs targeted by Pho92 are sufficient to delay their down-regulation and, in one case, to impact meiotic progression. Altogether, our results indicate that Pho92 facilitate the meiotic progression by accelerating the down-regulation of timely-regulated mRNAs during meiotic recombination.

molecular biology↗