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Lopes RRS, Silveira GDO, Eitler R, Vidal RS, Kessler A, Hinger S, Paris Z, Alfonzo JD, Polycarpo C. The essential function of the Trypanosoma brucei Trl1 homolog in procyclic cells is maturation of the intron-containing tRNATyr. RNA (NEW YORK, N.Y.) 2016; 22:1190-9. [PMID: 27284166 PMCID: PMC4931112 DOI: 10.1261/rna.056242.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/20/2016] [Indexed: 05/27/2023]
Abstract
Trypanosoma brucei, the etiologic agent of sleeping sickness, encodes a single intron-containing tRNA, tRNA(Tyr), and splicing is essential for its viability. In Archaea and Eukarya, tRNA splicing requires a series of enzymatic steps that begin with intron cleavage by a tRNA-splicing endonuclease and culminates with joining the resulting tRNA exons by a splicing tRNA ligase. Here we explored the function of TbTrl1, the T. brucei homolog of the yeast Trl1 tRNA ligase. We used a combination of RNA interference and molecular biology approaches to show that down-regulation of TbTrl1 expression leads to accumulation of intron-containing tRNA(Tyr) and a concomitant growth arrest at the G1 phase. These defects were efficiently rescued by expression of an "intronless" version of tRNA(Tyr) in the same RNAi cell line. Taken together, these experiments highlight the crucial importance of the TbTrl1 for tRNA(Tyr) maturation and viability, while revealing tRNA splicing as its only essential function.
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Affiliation(s)
- Raphael R S Lopes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Caixa Postal 68041, Brazil Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Caixa Postal 68041, Brazil
| | - Gilbert de O Silveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Caixa Postal 68041, Brazil Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Caixa Postal 68041, Brazil
| | - Roberta Eitler
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Caixa Postal 68041, Brazil
| | - Raphael S Vidal
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Caixa Postal 68041, Brazil
| | - Alan Kessler
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Scott Hinger
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Zdeněk Paris
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
| | - Juan D Alfonzo
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Carla Polycarpo
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Caixa Postal 68041, Brazil Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Caixa Postal 68041, Brazil
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Wemhoff S, Klassen R, Meinhardt F. DNA damage induced by the anticodon nuclease from a Pichia acaciae killer strain is linked to ribonucleotide reductase depletion. Cell Microbiol 2015; 18:211-22. [PMID: 26247322 DOI: 10.1111/cmi.12496] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/24/2015] [Accepted: 07/26/2015] [Indexed: 11/30/2022]
Abstract
Virus like element (VLE) encoded killer toxins of Pichia acaciae and Kluyveromyces lactis kill target cells through anticodon nuclease (ACNase) activity directed against tRNA(Gln) and tRNA(Glu) respectively. Not only does tRNA cleavage disable translation, it also affects DNA integrity as well. Consistent with DNA damage, which is involved in toxicity, target cells' mutation frequencies are elevated upon ACNase exposure, suggesting a link between translational integrity and genome surveillance. Here, we analysed whether ACNase action impedes the periodically and highly expressed S-phase specific ribonucleotide reductase (RNR) and proved that RNR expression is severely affected by PaT. Because RNR catalyses the rate-limiting step in dNTP synthesis, mutants affected in dNTP synthesis were scrutinized with respect to ACNase action. Mutations elevating cellular dNTPs antagonized the action of both the above ACNases, whereas mutations lowering dNTPs aggravated toxicity. Consistently, prevention of tRNA cleavage in elp3 or trm9 mutants, which both affect the wobble uridine modification of the target tRNA, suppressed the toxin hypersensitivity of a dNTP synthesis mutant. Moreover, dNTP synthesis defects exacerbated the PaT ACNase sensitivity of cells defective in homologous recombination, proving that dNTP depletion is responsible for subsequent DNA damage.
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Affiliation(s)
- Sabrina Wemhoff
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Roland Klassen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
| | - Friedhelm Meinhardt
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
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