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Mutation of two Mycoplasma arthritidis surface lipoproteins with divergent functions in cytadherence

Daniel W Bird1, Kelly Graber, Allison Knutson

  • 1Sanford School of Medicine, University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069, USA.

Infection and Immunity
|September 17, 2008
PubMed

Insights

Mycoplasma arthritidis uses Maa1 as a major adhesin for cell attachment. Maa2, however, appears to modulate adherence, potentially aiding in pathogen release during infection.

Area of Science:

  • Microbiology
  • Pathogenesis
  • Bacterial Adherence

Background:

  • Mycoplasma arthritidis is a rat pathogen causing acute polyarthritis.
  • Maa1 and Maa2 are membrane-bound lipoproteins previously implicated in M. arthritidis cytadherence.
  • Maa1 is a confirmed major adhesin, while Maa2's role was less clear.

Purpose of the Study:

  • To elucidate the specific roles of Maa1 and Maa2 in M. arthritidis cytadherence in vitro.
  • To investigate the functional significance of these lipoproteins in bacterial pathogenesis.

Main Methods:

  • Generation of insertion mutants for maa1 and maa2 genes using transposon mutagenesis.
  • In vitro adherence assays using rat L2 lung cells.
  • Complementation of mutants with wild-type alleles to confirm gene function.

Main Results:

  • The Maa1 mutant (KOMaa1) exhibited significantly reduced adherence to L2 cells.
  • The Maa2 mutant (KOMaa2) showed a fivefold increase in adherence compared to wild-type.
  • Complementation restored adherence levels to wild-type in both mutants.

Conclusions:

  • Maa1 is confirmed as a primary adhesin mediating M. arthritidis attachment to host cells.
  • Maa2 may possess a suppressive or modulatory function in adherence, potentially facilitating detachment from microcolonies during infection.
  • Understanding these adhesins is crucial for comprehending M. arthritidis pathogenesis.

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