• Heffron, Fred (PI)

    Project: Research project

    Project Details


    Transposition immunity is a relatively unstudied genetic phenomenon in
    bacteria. Tn3 transposition immunity is a cis acting mechanism which limits
    Tn3 insertion into a plasmid. We have shown that Tn3's terminal repeat can
    confer immunity to a plasmid. However, we also find that the transposition
    immunity phenotype can be affected by host sequences. During this granting
    period we will pursue a genetic approach, using techniques of in vitro and
    in vivo mutagenesis, to dissect the immunity sequence as well as host and
    plasmid sequences which also affect immunity. We will determine whether
    other transposons related to Tn3 show immunity and if so determine whether
    they show cross immunity to each other. We will determine to how large a
    DNA molecule Tn3 can confer immunity and whether there are other parameters
    which also affect immunity. For example, some naturally occurring plasmids
    are immune to Tn3 though they do not confer penicillin resistance. Through
    this genetic approach, as well as additional experiments, we will
    distinguish between the various models for how transposition immunity works.
    Effective start/end date3/1/842/28/87


    • National Institutes of Health
    • National Institutes of Health


    • Medicine(all)
    • Immunology and Microbiology(all)

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