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Fine mapping and DNA sequence of replication functions of Bacillus thuringiensis plasmid pTX14-3

S M Madsen1, L Andrup, L Boe

  • 1Department of Microbiology, Technical University of Denmark, Lyngby-Copenhagen.

Plasmid
|September 1, 1993
PubMed

Insights

Researchers identified a novel plasmid replication mechanism in Bacillus thuringiensis. The pTX14-3 plasmid

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Bacillus thuringiensis subspecies israelensis harbors cryptic plasmids, such as pTX14-3.
  • Small plasmids in gram-positive bacteria often replicate using single-stranded DNA intermediates.

Purpose of the Study:

  • To characterize the replication region of the pTX14-3 plasmid.
  • To identify and analyze the protein essential for pTX14-3 replication.
  • To investigate the single-strand origin (minus origin) of pTX14-3.

Main Methods:

  • Nucleotide sequencing of the replication region.
  • Deletion analysis to identify the replication protein.
  • Sequence comparison with known plasmid replicons and origins.

Main Results:

  • An open reading frame encoding a 636 bp replication protein was identified.
  • The pTX14-3 replication protein showed no homology to known replication proteins or plus origins.
  • The single-strand origin (minus origin) sequence was determined, showing partial homology to Bacillus subtilis plasmid pBAA1.
  • A locus suppressing multimer formation was minimized and sequenced.

Conclusions:

  • The pTX14-3 replicon represents a new family of single-stranded DNA plasmid replicons.
  • The identified replication protein and origin sequences offer insights into plasmid replication diversity.
  • Understanding pTX14-3 replication may aid in developing new genetic tools for Bacillus species.

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