Question

lex A is an E.coli gene whose product regulates the transcription of certain target genes that are located at different positions in the bacterial chromosome. Identified target genes appear to be involved in DNA repair and recombination. Under normal conditions, the LexA protein binds near and represses transcription of target genes; however, when the cell experiences significant DNA damage caused by environmental mutagens, the LexA protein is inactivated and transcription of the target genes occurs. Your research objective is to identify all of the target genes repressed by the LexA protein. (Assume that you have access to a DNA microarray consisting of sequences representing each of the genes in the E. coli genome.) As the starting point for your work, you isolate a lexA mutant strain that produces no functional LexA protein. Briefly describe an experiment that uses a functional genomics approach to identify all of the LexA target genes. Give the basic steps of the experiment and show how it would allow you to achieve your objective.