Insertional mutagenesis by random cloning of antibiotic resistance genes into the genome of the cyanobacterium Synechocystis strain PCC 6803
Abstract
The facultative heterotrophic cyanobacterium Synechocystis sp. strain PCC 6803 was transformed by HaeII Cmr fragments ligated at random to HaeII DNA fragments of the host genome. A similar transformation was done with an AvaII Kmr marker ligated to AvaII host DNA fragments. Integration of the resistance markers into the host genome led to a high frequency of stable Kmr and Cmr transformants. Physical analysis of individual transformants indicated that this result was due to homologous recombination by conversionlike events leading to insertion of the Cmr (or Kmr) gene between two HaeII (or AvaII) sites of the host genome, with precise deletion of the host DNA between these sites. In contrast, integrative crossover of circular DNA molecules with homology to the host DNA is very rare in this cyanobacterium. Strain PCC 6803 was shown to have about 12 genomic copies per cell in standard growth conditions, which complicates the detection of recessive mutations induced by chemical or UV mutagenesis. Random disruption of the host DNA by insertional transformation provides a convenient alternative to transposon mutagenesis in cyanobacteria and may help to overcome the difficulties encountered in generating recessive mutants by classica...Continue Reading
References
Tn1721 derivatives for transposon mutagenesis, restriction mapping and nucleotide sequence analysis.
Citations
Function and Regulation of Ferredoxins in the Cyanobacterium, Synechocystis PCC6803: Recent Advances
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Antimicrobial Resistance (ASM)
Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections.
Allergy & Infectious Diseases (ASM)
Allergies result from the hyperreactivity of the immune system to some environmental substance and can be life-threatening. Infectious diseases are caused by organisms including bacteria, viruses, fungi and parasites. They can be transmitted different ways, such as person-to-person. Here is the latest research on allergy and infectious diseases.