Scientific Reports (Jul 2017)

Mycobacterial DNA-binding protein 1 is critical for long term survival of Mycobacterium smegmatis and simultaneously coordinates cellular functions

  • Shymaa Enany,
  • Yutaka Yoshida,
  • Yoshitaka Tateishi,
  • Yuriko Ozeki,
  • Akihito Nishiyama,
  • Anna Savitskaya,
  • Takehiro Yamaguchi,
  • Yukiko Ohara,
  • Tadashi Yamamoto,
  • Manabu Ato,
  • Sohkichi Matsumoto

DOI
https://doi.org/10.1038/s41598-017-06480-w
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 11

Abstract

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Abstract Bacteria can proliferate perpetually without ageing, but they also face conditions where they must persist. Mycobacteria can survive for a long period. This state appears during mycobacterial diseases such as tuberculosis and leprosy, which are chronic and develop after long-term persistent infections. However, the fundamental mechanisms of the long-term living of mycobacteria are unknown. Every Mycobacterium species expresses Mycobacterial DNA-binding protein 1 (MDP1), a histone-like nucleoid associated protein. Mycobacterium smegmatis is a saprophytic fast grower and used as a model of mycobacterial persistence, since it shares the characteristics of the long-term survival observed in pathogenic mycobacteria. Here we show that MDP1-deficient M. smegmatis dies more rapidly than the parental strain after entering stationary phase. Proteomic analyses revealed 21 upregulated proteins with more than 3-fold in MDP1-deficient strain, including DnaA, a replication initiator, NDH, a NADH dehydrogenase that catalyzes downhill electron transfer, Fas1, a critical fatty acid synthase, and antioxidants such as AhpC and KatG. Biochemical analyses showed elevated levels of DNA and ATP syntheses, a decreased NADH/NAD+ ratio, and a loss of resistance to oxidative stress in the MDP1-knockout strain. This study suggests the importance of MDP1-dependent simultaneous control of the cellular functions in the long-term survival of mycobacteria.