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Published on: October 4, 2018
Mouse Trmt2B protein is a dual specific mitochondrial metyltransferase responsible for m5U formation in both tRNA and
Ivan Laptev1,2, Ekaterina Shvetsova3, Sergey Levitskii4
1Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow Region, Russia.
Abstract:
RNA molecules of all species contain modified nucleotides and particularly m5U residues. The vertebrate mitochondrial small subunit rRNA contains m5U nucleotide in a unique site. In this work we found an enzyme, TRMT2B, responsible for the formation of this nucleotide and m5U residues in a number of mitochondrial tRNA species. Inactivation of the Trmt2B gene leads to a reduction of the activity of respiratory chain complexes I, III and IV, containing the subunits synthesized by the mitochondrial protein synthesis apparatus. Comparative sequence analysis of m5U-specific RNA methyltransferases revealed an unusual evolutionary pathway of TRMT2B formation which includes consecutive substrate specificity switches from the large subunit rRNA to tRNA and then to the small subunit rRNA.
Insights
Researchers identified TRMT2B as the enzyme responsible for creating m5U modifications in mitochondrial RNA. Gene inactivation impaired respiratory chain complexes, revealing TRMT2B
Area of Science:
- Mitochondrial biology
- RNA modification
- Enzymology
Background:
- Modified nucleotides, including m5U, are crucial components of RNA molecules across all species.
- Vertebrate mitochondrial small subunit rRNA possesses a unique m5U modification site.
Purpose of the Study:
- To identify the enzyme responsible for the unique m5U modification in vertebrate mitochondrial small subunit rRNA.
- To investigate the role of this enzyme in mitochondrial tRNA modification and function.
- To elucidate the evolutionary history of m5U-specific RNA methyltransferases.
Main Methods:
- Enzyme activity assays to identify TRMT2B.
- Gene knockout studies of Trmt2B in vertebrates.
- Analysis of respiratory chain complex activity.
- Comparative sequence analysis of m5U-specific RNA methyltransferases.
Main Results:
- TRMT2B was identified as the enzyme catalyzing the formation of m5U in mitochondrial small subunit rRNA and several mitochondrial tRNA species.
- Inactivation of the Trmt2B gene resulted in decreased activity of respiratory chain complexes I, III, and IV.
- Comparative sequence analysis indicated an unusual evolutionary path for TRMT2B, involving sequential substrate specificity changes.
Conclusions:
- TRMT2B is essential for m5U modification in mitochondrial RNA, impacting mitochondrial function.
- The evolutionary trajectory of TRMT2B highlights substrate adaptability in RNA methyltransferases.
- Understanding TRMT2B function is vital for comprehending mitochondrial gene expression and cellular respiration.
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