The unpredictability of downstream effects
by Douglas Axe (2010-05-07)
I have a couple of questions/comments about the kinds of mutations you found (as listed in Table 6). First, any ideas as to what's going on with the A1584C mutation? You say that this changes the second codon of the tet orf, and it can't be a nonsense mutation (because stop codons don't use C). So, what amino-acid substitution results from this change?
Possibly this mutation has an effect on the structure of the mRNA. Have you looked into this at all? I'm only asking because this is a striking effect from an apparently innocuous change.
Also, from fig3 it appears that the metabolic load of carrying this plasmid is only partly attributable to the gene of interest, trpA. So presumably the cost could be reduced if the upstream genes weren't there. Any guess as to whether that might have changed the result?
Replies
Re:The unpredictability of downstream effects
by Ann K Gauger (2010-05-10)
Thanks for the comment. I agree that it is unexpected that a single base change in the second codon should shut down expression to such an extent. The base change is from AAA (lysine) to CAA (glutamine).... Read more
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