RNase MRP cleaves pre-tRNASer-Met in the tRNA maturation pathway

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Ribonuclease mitochondrial RNA processing (RNase MRP) is a vital ribonucleoprotein complex essential for cell viability.
• It plays a role in the maturation of various RNA types, including ribosomal RNA.

Purpose of the Study:

• To investigate the role of RNase MRP in tRNA maturation.
• To elucidate the structural and functional aspects of RNase MRP.

Main Methods:

• Utilized a temperature-sensitive mutant of rmp1 in Schizosaccharomyces pombe to observe precursor accumulation.
• Purified RNase MRP holoenzyme for in vitro cleavage assays.
• Performed mass spectrometry-based ribonucleoproteomic analysis.
• Conducted limited nucleolysis to identify the catalytic core.

Main Results:

• A temperature-sensitive mutant accumulated dimeric tRNA precursor, pre-tRNA(Ser-Met), indicating a role for RNase MRP in tRNA processing.
• Purified RNase MRP directly and selectively cleaved pre-tRNA(Ser-Met).
• RNase MRP comprises one RNA molecule and 11 proteins, including the novel component Rpl701.
• An active catalytic core was identified, consisting of specific RNA fragments and 8 proteins.

Conclusions:

• RNase MRP is directly involved in the in vivo maturation of specific tRNAs.
• The study identified a novel protein component (Rpl701) and delineated the catalytic core of RNase MRP, advancing understanding of its structure-function relationship.