Question

You artificially increase the level of σ^32 in an E. coli culture. What will you expect to see?

(a) rpo H transcription permanently inhibited

(b) cdc transcription constitutively turned on

(c) rpo H temporarily activated

(d) cdc 6 permanently turned off

The question was posed to me in unit test.

I'm obligated to ask this question of Transcription in Prokaryotes : Sigma Factor topic in portion Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

Correct option is (c) rpo H temporarily activated

Easy explanation: σ^32 is necessary for transcribing genes like rpo H that helps in surviving heat shock while it doesn’t act on cdc6 that has a role in replication. As σ^32 is unstable it temporarily turns on rho H till the concentration ratio of σ^32 and σ^70 returns to normal.