title: Transfer-messenger RNA and SmpB mediate bacteriostasis in Escherichia coli cells against tRNA cleavage.
abstract: RNAs, such as mRNA, rRNA and tRNA, are essential macromolecules for cell survival and maintenance. Any perturbation of these molecules, such as by degradation or mutation, can be toxic to cells and may occasionally induce cell death. Therefore, cells have mechanisms known as quality control systems to eliminate abnormal RNAs. Although tRNA is a stable molecule, the anticodon loop is quite susceptible to tRNA-targeting RNases such as colicin E5 and colicin D. However, the mechanism underlying cellular reaction to tRNA cleavage remains unclear. It had long been believed that tRNA cleavage by colicins E5 and D promptly induces cell death because colony formation of the sensitive cells is severely reduced; this indicates that cells do not resist the tRNA cleavage. Here, we show that Escherichia coli cells enter a bacteriostatic state against the tRNA cleavage of colicins D and E5. The bacteriostasis requires small protein B (SmpB) and transfer-messenger RNA (tmRNA), which are known to mediate trans-translation. Furthermore, another type of colicin, colicin E3 cleaving rRNA, immediately reduces the viability of sensitive cells. Moreover, nascent peptide degradation has an additive effect on bacteriostasis. Considering the recent observation that tRNA cleavage may be used as a means of cell-to-cell communication, tRNA cleavage could be used by bacteria not only to dominate other bacteria living in the same niche, but also to regulate growth of their own or other cells.
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Fusako
authors.initials: F
authors.lastname: Sakai
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Risa
authors.initials: R
authors.lastname: Sugita
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Jung-Wei
authors.initials: JW
authors.lastname: Chang
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Tsumadori
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hidaka
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Masaki
mesh_terms: D003087:Colicins / Q000378:metabolism; D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism*; D006868:Hydrolysis; D050296:Microbial Viability; D012329:RNA, Bacterial / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D003087:Colicins; D012329:RNA, Bacterial; D016601:RNA-Binding Proteins; C430328:small protein B; C096222:tmRNA; D012343:RNA, Transfer