title: Digestion of extracellular DNA is required for giant colony formation of Staphylococcus aureus.
abstract: Staphylococcus aureus spreads on soft agar surfaces and forms giant colonies. Here, we examined the inhibitory role of extracellular DNA on the colony spreading activity. The double-deletion mutation of nuc1 and nuc2, which encode secretory nucleases, increased extracellular DNA and showed a decreased ability to form giant colonies. The addition of DNase I or micrococcal nuclease to the soft agar restored the ability of the nuc1-nuc2 double mutant to form giant colonies. In addition, the promoter activities of nuc1 and nuc2 in the wild-type strain were elevated in the peripheral region of the giant colony. These findings suggest that the digestion of extracellular DNA by secretory nucleases is required for the colony spreading activity of S. aureus.
authors.affiliation: Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-Chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Chikara
authors.initials: C
authors.lastname: Kaito
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirano
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Omae
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sekimizu
mesh_terms: D000362:Agar; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D006801:Humans; D006868:Hydrolysis; D013211:Staphylococcus aureus / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D000362:Agar; D003851:Deoxyribonucleases