The fission yeast MTREC complex targets CUTs and unspliced pre-mRNAs to the nuclear exosome

Area of Science:

• Molecular Biology
• RNA Biology
• Gene Regulation

Background:

• Cryptic unstable transcripts (CUTs) are rapidly degraded by the nuclear exosome.
• The precise mechanisms for targeting CUTs to the nuclear exosome remain incompletely understood.

Purpose of the Study:

• To elucidate the primary nuclear exosome targeting complex for CUTs and unspliced pre-mRNAs in Schizosaccharomyces pombe.
• To investigate the role of the MTREC complex in RNA quality control and degradation pathways.

Main Methods:

• Biochemical assays to determine RNA-binding specificities of the MTREC complex.
• Analysis of physical interactions between MTREC, the nuclear exosome, and other RNA-processing complexes.
• Genetic studies in Schizosaccharomyces pombe to assess the functional significance of MTREC in RNA degradation.

Main Results:

• The MTREC complex is identified as the major nuclear exosome targeting complex for CUTs and unspliced pre-mRNAs in fission yeast.
• MTREC specifically binds to CUTs, meiotic mRNAs, and unspliced pre-mRNAs, facilitating their degradation by the nuclear exosome.
• The TRAMP complex plays a minor role in targeting these RNAs compared to MTREC.
• MTREC physically interacts with the nuclear exosome and RNA-processing factors, linking RNA processing to degradation.

Conclusions:

• The MTREC complex plays a central role in RNA quality control by recognizing and eliminating aberrant transcripts like CUTs.
• This study reveals MTREC as a key component of the nuclear RNA surveillance machinery, coupling RNA processing with degradation.
• The findings underscore the evolutionarily conserved importance of MTREC in maintaining transcriptome integrity.