1. Want to know what the Berkeley iGEM is doing? Go to our page.

2. The Riboregulator Method of translational control of gene expression
cis-repressive sequence (“lock”) upstream of a gene’s coding region forms a hairpin, sequestering the ribosome binding site
trans-activating (“key”) mRNA strand binds and opens the hairpin thus allowing access to the RBS.
Highly specific activation occurs. Very similar lock and key pair sequences do not exhibit crosstalk
Isaacs et al., Nature Biotechnology, 2004

3. Results with lock3/key3 Strain Fluorescence no plasmids 31 lock3RFP 44
key3 + lock3RFP 78
OnRFP 6415
key3 +
lock3-RFP

4. Improved locks and keys
Frame of homology
Presence of hairpin
Position of promoter
Degree of homology
Position of terminator
Transcriptional fusion
Length of spacer
Distance from RBS

5. Useful Specs? Gain = FL(lock + key) / FL(lock)
Gain = FL(lock + key – BG) / FL(lock – BG)
% Recovery = FL(lock + key) / FL(OnRFP)

6. New key architectures
Increases effective key concentration; gene dosing
13x, δ=0.5
83x, δ=4
11%, δ=.5%
Increases stability
8x, δ=1
30x, δ=5
9%, δ=1%

7. Unanswered questions
Is 100% recovery possible? Limits to gain? Why is [mRNA] lower? Termination, RNAses, etc. QPCR
How does FL vary over pop.? Actual FL levels? Flow Cytometry
Is there a FL-OD relationship?  Time course