Now that the meningococcal genome sequence has been completed, the lack of
a suitable method for saturation mutagenesis remains a major obstacle to th
e unraveling of the pathogenic propensity of Neisseria meningitidis. Here,
we demonstrate that in vitro Himar1 mariner transposition on chromosomal or
PCR-amplified meningococcal DNA, which is subsequently reintroduced into N
. meningitidis by natural transformation, is an extremely efficient mutagen
esis method. Southern blot analysis, sequencing the Himar1 insertion point
in numerous transposition mutants, and a limited screening of the mutant li
braries for clones impaired in maltose catabolism confirmed that Himar1 tra
nsposed randomly in N. meningitidis. Taken together, these data demonstrate
that Himar1 in vitro transposition can lead to the exhaustive mutagenesis
of N. meningitidis, allowing for the first time a genomic-scale mutational
analysis of this important human pathogen.