title: Bacillus subtilis mutants harbouring a single copy of the rRNA operon exhibit severe defects in growth and sporulation.
abstract: The number of copies of rRNA genes in bacterial genomes differs greatly among bacterial species. It is difficult to determine the functional significance of the heterogeneity of each rRNA operon fully due to the existence of multiple rRNA operons and because the sequence heterogeneity among the rRNA genes is extremely low. To overcome this problem, we sequentially deleted the ten rrn operons of Bacillus subtilis and constructed seven mutant strains that each harboured a single rrn operon (either rrnA, B, D, E, I, J or O) in their genome. The growth rates and sporulation frequencies of these mutants were reduced drastically compared with those of the wild-type strain, and this was probably due to decreased levels of ribosomes in the mutants. Interestingly, the ability to sporulate varied significantly among the mutant strains. These mutants have proved to be invaluable in our initial attempts to reveal the functional significance of the heterogeneity of each rRNA operon.
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nanamiya
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Sato
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Masuda
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Sato
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Wada
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Natori
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Katano
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Genki
authors.initials: G
authors.lastname: Akanuma
authors.affiliation: Laboratory of Molecular Genetics and Research Information Center for Extremophile, College of Science, Rikkyo University, Toshima-ku Nishi-ikebukuro 3-34-1, Tokyo 171-8501, Japan.
authors.forename: Fujio
authors.initials: F
authors.lastname: Kawamura
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D017353:Gene Deletion; D018628:Gene Dosage; D009154:Mutation; D012270:Ribosomes / Q000235:genetics; D013171:Spores, Bacterial / Q000254:growth & development; D012407:rRNA Operon