New methods for tightly regulated gene expression and highly efficient chromosomal integration of cloned genes for Methanosarcina species

Adam M. Guss, Michael Rother, Jun Kai Zhang, Gargi Kulkarni, William W. Metcalf

Research output: Contribution to journalArticlepeer-review

Abstract

A highly efficient method for chromosomal integration of cloned DNA into Methanosarcina spp. was developed utilizing the site-specific recombination system from the Streptomyces phage φC31. Host strains expressing the φC31 integrase gene and carrying an appropriate recombination site can be transformed with non-replicating plasmids carrying the complementary recombination site at efficiencies similar to those obtained with self-replicating vectors. We have also constructed a series of hybrid promoters that combine the highly expressed M. barkeri PmcrB promoter with binding sites for the tetracycline-responsive, bacterial TetR protein. These promoters are tightly regulated by the presence or absence of tetracycline in strains that express the tetR gene. The hybrid promoters can be used in genetic experiments to test gene essentiality by placing a gene of interest under their control. Thus, growth of strains with tetR-regulated essential genes becomes tetracycline-dependent. A series of plasmid vectors that utilize the site-specific recombination system for construction of reporter gene fusions and for tetracycline regulated expression of cloned genes are reported. These vectors were used to test the efficiency of translation at a variety of start codons. Fusions using an ATG start site were the most active, whereas those using GTG and TTG were approximately one half or one fourth as active, respectively. The CTG fusion was 95% less active than the ATG fusion.

Original languageEnglish (US)
Pages (from-to)193-203
Number of pages11
JournalArchaea
Volume2
Issue number3
DOIs
StatePublished - Dec 2008

Keywords

  • Essential gene
  • Genetics
  • Site-specific recombination
  • tetR

ASJC Scopus subject areas

  • Microbiology
  • Physiology
  • Ecology, Evolution, Behavior and Systematics

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