For the mutations in the 5\' UTR of the trp operon given below, explain the effe
ID: 91314 • Letter: F
Question
For the mutations in the 5' UTR of the trp operon given below, explain the effect on expression of the trp operon relative to wildtype (increased, decreased, or unchanged). Assume medium levels of tryptophan, such that TrpR (repressor) is inactive and attenuation is active. a) A mutation in region 2 such that it cannot bind with region 3. b) A mutation in region 4 such that it cannot bind with region 3. c) Insertion of T - A basepairs immediately after region 3, such that uracils are transcribed. This insertion does not change the stem - loop formation properties of regions 1, 2, 3 or 4.Explanation / Answer
a) When region 2 pairs with region 3, the resulting hairpin acts as an antiterminator allowing for transcription to proceed so if mutation occur in region 2 such that it cannot bind to 3 thus it result in decreased expression.
b) The hairpin structure formed by the pairing of region 3 with region 4 results in a terminator being formed that stops transcription. thus if muation occur in 3 so that it cannot bind to 4 thus termination does not stop. increased expression
c) unchanged.