lex A is an E. coli gene whose product regulates thetranscription of certain target
genes that are located at different positions in the bacterialchromosome.
Identified target genes appear to be involved in DNA repair andrecombination.
Under normal conditions, the LexA protein binds near andrepresses
transcription of target genes; however, when the cellexperiences significant
DNA damage caused by environmental mutagens, the LexA proteinis
inactivated and transcription of the target genes occurs. Yourresearch objective
is to identify all of the target genes repressed by the LexAprotein. (Assume that
you have access to a DNA microarray consisting of sequencesrepresenting each
of the genes in the E. coli genome.) As the starting point foryour work, you
isolate a lexA mutant strain that produces no functional LexAprotein.
a) Briefly describe an experiment that uses a functionalgenomics approach to identify all
of the LexA target genes.
b) Give the basic steps of the experiment and show how it
would allow you to achieve your objective