title: tRNA is a new target for cleavage by a MazF toxin.
abstract: Toxin-antitoxin (TA) systems play key roles in bacterial persistence, biofilm formation and stress responses. The MazF toxin from the Escherichia coli mazEF TA system is a sequence- and single-strand-specific endoribonuclease, and many studies have led to the proposal that MazF family members exclusively target mRNA. However, recent data indicate some MazF toxins can cleave specific sites within rRNA in concert with mRNA. In this report, we identified the repertoire of RNAs cleaved by Mycobacterium tuberculosis toxin MazF-mt9 using an RNA-seq-based approach. This analysis revealed that two tRNAs were the principal targets of MazF-mt9, and each was cleaved at a single site in either the tRNA(Pro14) D-loop or within the tRNA(Lys43) anticodon. This highly selective target discrimination occurs through recognition of not only sequence but also structural determinants. Thus, MazF-mt9 represents the only MazF family member known to target tRNA and to require RNA structure for recognition and cleavage. Interestingly, the tRNase activity of MazF-mt9 mirrors basic features of eukaryotic tRNases that also generate stable tRNA-derived fragments that can inhibit translation in response to stress. Our data also suggest a role for tRNA distinct from its canonical adapter function in translation, as cleavage of tRNAs by MazF-mt9 downregulates bacterial growth.
authors.affiliation: Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, USA.
authors.forename: Jason M
authors.identifier: http://orcid.org/0000-0002-8072-9613
authors.initials: JM
authors.lastname: Schifano
authors.affiliation: Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, USA.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Cruz
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, NJ, USA Department of Genetics, Rutgers University, Piscataway, NJ, USA.
authors.forename: Irina O
authors.initials: IO
authors.lastname: Vvedenskaya
authors.affiliation: Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA, USA.
authors.forename: Regina
authors.initials: R
authors.lastname: Edifor
authors.affiliation: Department of Computer Science, University of Massachusetts Boston, Boston, MA, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Ouyang
authors.affiliation: Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA, USA.
authors.forename: Robert N
authors.identifier: http://orcid.org/0000-0001-8994-7046
authors.initials: RN
authors.lastname: Husson
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, NJ, USA Department of Genetics, Rutgers University, Piscataway, NJ, USA Member, Rutgers Cancer Institute of New Jersey, NJ, USA.
authors.forename: Bryce E
authors.initials: BE
authors.lastname: Nickels
authors.affiliation: Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ, USA Member, Rutgers Cancer Institute of New Jersey, NJ, USA nancy.woychik@rutgers.edu.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Woychik
mesh_terms: D000926:Anticodon / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015152:Blotting, Northern; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000926:Anticodon; D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012343:RNA, Transfer; D004722:Endoribonucleases; C000601629:MazF protein, Mycobacterium tuberculosis