In bacteria, finely tuned and coordinated expression of genes from different operons is required to build a nanomachine, such as the flagella. Many factors control the expression of each of these operons and detailed study of just one operon requires impressive effort. To simplify the study of gene cluster expression, Kalir and coworkers tracked the expression of these operons in real time using transcriptional fusions of different promoters to gfp. The authors followed the expression of 14 different flagella-related promoters in real time using a fluorimeter, which allowed for non-destructive observation of gene expression. The order of expression of each operon was determined by clustering promoters with similar expression profiles. This approach has enabled many subsequent studies in microbial gene expression. -KJM
Kalir, S et al. 2001.
Ordering Genes in a Flagella Pathway by Analysis of Expression Kinetics from Living Bacteria. Science. 292, 2080-2083. doi: 10.1126/science.1058758