Measurements of transposition frequency of insertion sequence IS1 by GFP hop-on assay.

Transposons play a significant role in the evolution of bacterial genomes. Quantifying frequency of transpositional events caused by a transposon will facilitate understanding its role. Here, we report successful measurement of the frequency of IS1 transposition using "GFP hop-on assay" in which transposition-dependent GFP expression is monitored by FACS. This assay allows easy assessment of IS transposition into the chromosomal DNA on a single-cell scale; this is an advantage over other conventional methods to measure transposition frequency.