title: Involvement of the Escherichia coli folate-binding protein YgfZ in RNA modification and regulation of chromosomal replication initiation.
abstract: The Escherichia coli hda gene codes for a DnaA-related protein that is essential for the regulatory inactivation of DnaA (RIDA), a system that controls the initiation of chromosomal replication. We have identified the ygfZ gene, which encodes a folate-binding protein, as a suppressor of hda mutations. The ygfZ null mutation suppresses an hda null mutation. The over-initiation and abortive elongation phenotypes conferred by the hda mutations are partially suppressed in an hda ygfZ background. The accumulation of the active form of DnaA, ATP-DnaA, in the hda mutant is suppressed by the disruption of the ygfZ gene, indicating that YgfZ is involved in regulating the level of ATP-DnaA. Although ygfZ is not an essential gene, the ygfZ disruptant grows slowly, especially at low temperature, demonstrating that this gene is important for cellular proliferation. We have identified mnmE (trmE) as a suppressor of the ygfZ disruption. This gene encodes a GTPase involved in tRNA modification. Examination of RNA modification in the ygfZ mutant reveals reduced levels of 2-methylthio N(6)-isopentenyladenosine [corrected] indicating that YgfZ participates in the methylthio-group formation of this modified nucleoside in some tRNAs. These results suggest that YgfZ is a key factor in regulatory networks that act via tRNA modification.
authors.affiliation: Department of Biology, Graduate School of Science, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Tomotake
authors.initials: T
authors.lastname: Ote
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Yoshiho
authors.initials: Y
authors.lastname: Ikeuchi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Su'etsugu
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Suzuki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Katayama
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kato
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D058973:Folate Receptors, GPI-Anchored; D020558:GTP Phosphohydrolases / Q000378:metabolism; D009154:Mutation; D012329:RNA, Bacterial / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D018741:Replication Origin
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; D058973:Folate Receptors, GPI-Anchored; D012329:RNA, Bacterial; D011956:Receptors, Cell Surface; C509203:YgfZ protein, E coli; D012343:RNA, Transfer; D020558:GTP Phosphohydrolases