Reactome | tRNA processing

tRNA processing

Stable Identifier

R-HSA-72306

DOI

10.3180/R-HSA-72306.3

Type

Pathway

Species

Homo sapiens

ReviewStatus

5/5

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Genes encoding transfer RNAs (tRNAs) are transcribed by RNA polymerase III in the nucleus and by mitochondrial RNA polymerase in the mitochondrion.
In the nucleus transcription reactions produce precursor tRNAs (pre-tRNAs) that have extra 5' leaders, 3' trailers, and, in some cases, introns which are removed by enzymes and enzyme complexes: RNase P cleaves the 5' leader, RNase Z cleaves the 3' trailer, TRNT1 polymerizes CCA onto the resulting 3' end, the TSEN complex cleaves at each end of the intron, and the tRNA ligase complex ligates the resulting exons (reviewed in Rossmanith et al. 1995, Phizicky and Hopper 2010, Suzuki et al. 2011, Abbott et al. 2014, Li and Mason 2014). The nucleotides within tRNAs undergo further chemical modifications such as methylation and deamination by a diverse set of enzymes (reviewed in Helm and Alfonzo 2014, Boschi-Muller and Motorin 2013). The order of events for each tRNA is not fully known and the understanding of the overall process is complicated by the retrograde (cytosol to nucleus) transport of tRNAs.
In the mitochondrial matrix transcription produces long precursor RNAs, H strand transcripts and an L strand transcript, that are cleaved by mitochondrial RNase P (an entirely proteinaceous complex), ELAC2, and other nucleases to yield 12S rRNA, 16S rRNA, mRNAs, and pre-tRNAs lacking 3' CCA sequences (reviewed in Van Haute et al. 2015). TRNT1 polymerizes an untemplated CCA sequence onto the 3' ends of the pre-tRNAs and chemical modifications are made to several nucleotides in the tRNAs.

Literature References

PubMed ID	Title	Journal	Year
24490730	Chemistry enters nucleic acids biology: enzymatic mechanisms of RNA modification Boschi-Muller, S, Motorin, Y	Biochemistry Mosc.	2013
26016801	Mitochondrial transcript maturation and its disorders Van Haute, L, Pearce, SF, Powell, CA, D'Souza, AR, Nicholls, TJ, Minczuk, M	J. Inherit. Metab. Dis.	2015
21910628	Human mitochondrial tRNAs: biogenesis, function, structural aspects, and diseases Suzuki, T, Nagao, A, Suzuki, T	Annu. Rev. Genet.	2011
24898039	The pivotal regulatory landscape of RNA modifications Li, S, Mason, CE	Annu Rev Genomics Hum Genet	2014
7759547	Human mitochondrial tRNA processing Rossmanith, W, Tullo, A, Potuschak, T, Karwan, R, Sbisà, E	J. Biol. Chem.	1995
20810645	tRNA biology charges to the front Phizicky, EM, Hopper, AK	Genes Dev.	2010
24917879	Transfer RNA and human disease Abbott, JA, Francklyn, CS, Robey-Bond, SM	Front Genet	2014
24315934	Posttranscriptional RNA Modifications: playing metabolic games in a cell's chemical Legoland Helm, M, Alfonzo, JD	Chem. Biol.	2014