FIG. 2.
The plaA locus in L. pneumophila and recombinant E. coli. The upper line represents a 5-kb region of the L. pneumophila chromosome that contains the lysophospholipase A gene (plaA), along with the location of relevant restriction enzyme sites. The dashed line represents the DNA region that we sequenced and have deposited in the GenBank database. The arrows below this line depict the relative location, size, and orientation of plaA and neighboring genes. The thick lines at the bottom of the figure represent the segments of Legionella DNA that were cloned into plasmid vectors. Plasmid pAF3 contained a Kmr gene cassette in place of the Legionella sequences that normally exist between the indicated Bst98I sites. The + and − symbols denote whether supernatants from the recombinant E. coli exhibited increased lysophospholipase A activity.