Discovering essential and infection-related genes

Transposon-based approaches are very powerful for identification of essenti al and infection-related genes in bacteria, particularly in the context of microbial genomics. We describe recent progress in several of these approac hes, and their underlying principles. The essential gene test (EGT) is a tr ansposon-based technique that can rapidly identify a nucleotide sequence fr om a database as essential or dispensable. Also, variations of in vitro tra nsposon mutagenesis applications, such as genomic analysis and mapping by i n vitro transposition (GAMBIT), are described. The development of technique s including PCR-based signature-tagged mutagenesis is now used to find esse ntial virulence genes in different bacterial hosts. These approaches form t he basis for the identification of microbial targets in development of nove l antimicrobials and vaccines by the biotechnology and pharmaceutical indus try.