Effect of Bacillus subtilis BsuM restriction-modification on plasmid transfer by polyethylene glycol-induced protoplast fusion

Tomoko Maehara, Mitsuhiro Itaya, Mitsuo Ogura, Teruo Tanaka

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3 Citations (Scopus)


Polyethylene glycol (PEG)-induced cell fusion is a promising method to transfer larger DNA from one cell to another than conventional genetic DNA transfer systems. The laboratory strain Bacillus subtilis 168 contains a restriction (R) and modification (M) system, BsuM, which recognizes the sequence 5'-CTCGAG-3'. To study whether the BsuM system affects DNA transfer by the PEG-induced cell fusion between R +M + and R -M - strains, we examined transfer of plasmids pHV33 and pLS32neo carrying no and eight BsuM sites, respectively. It was shown that although the transfer of pLS32neo but not pHV33 from the R -M - to R +M + cells was severely restricted, significant levels of transfer of both plasmids from the R +M + to R -M - cells were observed. The latter result shows that the chromosomal DNA in the R -M - cell used as the recipient partially survived restriction from the donor R +M + cell, indicating that the BsuM R -M - strain is useful as a host for accepting DNA from cells carrying a restriction system(s). Two such examples were manifested for plasmid transfer from Bacillus circulans and Bacillus stearothermophilus strains to a BsuM-deficient mutant, B. subtilis RM125.

Original languageEnglish
Pages (from-to)49-55
Number of pages7
JournalFEMS microbiology letters
Issue number1
Publication statusPublished - 2011 Dec 1



  • B. subtilis
  • BsuM restriction
  • Protoplast fusion
  • pHV33
  • pLS32

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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