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Published on: October 14, 2011

Plasmid-to-chromosome gene transfer in Haemophilus influenza during growth

M Balganesh, L Arrigoni, J K Setlow

    Journal of Bacteriology
    |October 1, 1986
    PubMed

    Insights

    Homologous recombination between plasmids and the host chromosome occurred in Rec+ rec-2 mutants but was absent in rec-1 mutants. This process, crucial for integrating antibiotic resistance genes, happened at a low level during cell growth.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Genetics

    Background:

    • Homologous recombination is a key genetic process for DNA repair and genome stability.
    • Plasmids can integrate into host chromosomes, a phenomenon influenced by recombination machinery.
    • Antibiotic resistance markers are often used to track genetic modifications and selection.

    Purpose of the Study:

    • To investigate the role of specific Rec proteins in plasmid-chromosome recombination.
    • To determine the conditions under which plasmid integration occurs.
    • To understand the genetic basis of recombination efficiency in bacterial mutants.

    Main Methods:

    • Utilizing bacterial mutants with defined defects in recombination pathways (rec-1 and rec-2).
    • Employing plasmids with homologous regions designed for chromosomal integration.
    • Assessing recombination frequency by monitoring antibiotic resistance gene expression post-integration.

    Main Results:

    • Low-level recombination between homologous plasmid regions and the host chromosome was observed during cell growth.
    • Recombination occurred in wild-type (Rec+) and rec-2 mutant strains.
    • Recombination was abolished in rec-1 mutant strains, indicating its essential role.

    Conclusions:

    • The rec-1 gene product is essential for detectable plasmid-chromosome recombination.
    • Plasmid integration via homologous recombination is a low-frequency event during normal cell growth.
    • The rec-2 mutation does not prevent, but may modulate, this recombination process.

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