title: Ribosome modulation factor, an important protein for cell viability encoded by the polyamine modulon.
abstract: We searched for proteins whose synthesis is enhanced by polyamines at the stationary phase of cell growth using an Escherichia coli polyamine-requiring mutant in which cell viability is greatly decreased by polyamine deficiency. The synthesis of ribosome modulation factor (RMF) was strongly enhanced by polyamines at the level of translation at the stationary phase of cell growth. In rmf mRNA, a Shine-Dalgarno (SD) sequence is located 11 nucleotides upstream of the initiation codon AUG. When the SD sequence was moved to the more common position 8 nucleotides upstream of the initiation codon, the degree of polyamine stimulation was reduced, although the level of RMF synthesis was markedly increased. Polyamine stimulation of RMF synthesis was found to be caused by a selective structural change of the bulged-out region of the initiation site of rmf mRNA. The decrease in cell viability caused by polyamine deficiency was prevented by the addition of a modified rmf gene whose synthesis is not influenced by polyamines. The results indicate that polyamines enhance cell viability of E. coli at least in part by enhancing RMF synthesis.
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, 15-8 Shiomi-cho, Choshi, Chiba 288-0025, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Terui
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Tabei
authors.forename: Mariko
authors.initials: M
authors.lastname: Akiyama
authors.forename: Kyohei
authors.initials: K
authors.lastname: Higashi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tomitori
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Ishihama
authors.forename: Kazuei
authors.initials: K
authors.lastname: Igarashi
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
mesh_terms: D015317:Biogenic Polyamines / Q000378:metabolism / Q000494:pharmacology; D018387:Codon, Initiator / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics; D012329:RNA, Bacterial / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid / Q000502:physiology*; D012269:Ribosomal Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D015317:Biogenic Polyamines; D018387:Codon, Initiator; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D038621:Regulatory Sequences, Ribonucleic Acid; D012269:Ribosomal Proteins; C063545:ribosome modulation factor, E coli