For each of the E. coli strains below, determine the effect ofthe genotype on expression of the trpE and trpC genes in thepresence and absence of tryptophan. In the wild-type strain(genotype: R+ P+ O+ att+ trpE+ trpC+), the trpE and trpC genes arefully induced in the absence of tryptophan and fully repressed inthe presence of tryptophan.
Key:
R = functional repressor gene; Rn = product cannot bind tryptophan;R- = product cannot bind operator
O = functional operator; O- = operator cannot bind repressorprotein
att = functional attenuator; att- = a deletion of the attenuatorsequence
P = functional promoter; P- = a deletion of the trp operonpromoter
trpE- and trpC- = produce non-functional protein products
1) R+ P- O+ att+ trpE+ trpC+
2) R- P+ O+ att+ trpE+ trpC+
3) Rn P+ O+ att+ trpE+ trpC+
4) R- P+ O+ att- trpE+ trpC+
5) R+ P+ O- att+ trpE+ trpC- / R- P+ O+ att+ trpE- trpC+
6) R+ P- O+ att+ trpE+ trpC- / R- P+ O+ att+ trpE- trpC+
7) R+ P+ O- att- trpE+ trpC- / R- P+ O- att+ trpE- trpC+
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (-), trpC (-); No Trp = trpE (+), trpC (+)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (-), trpC (-); No Trp = trpE (+), trpC (+)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (-), trpC (-); No Trp = trpE (-), trpC (-)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (-), trpC (-); No Trp = trpE (-), trpC (+)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (+), trpC (-); No Trp = trpE (+), trpC (+)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (+), trpC (+); No Trp = trpE (+), trpC (+)
- 1. 2. 3. 4. 5. 6. 7.
Trp = trpE (-), trpC (-); No Trp = trpE (+), trpC (+)