Saturday, September 20, 2014

The mystery solved?



Well, I think I get it now. I was getting an odd phenotype for the Δhfq sxy-1 double mutant that suggested that this mutant was more competent than the sxy-1 single mutant. This is weird since knocking out Hfq in all other conditions tested so far has a negative effect. I tested the other hypercompetent sxy point mutations in a Δhfq background and again, I only see a negative effect:





And of course...

This has been eating at me for a long time now. Last lab meeting, I think it was Rosie who asked whether or not the Δhfq sxy-1 strain was accidently mixed-up with the Δhfq murE749 strain. Thinking about it more, I realized that when Rosie had originally preformed the initial characterization of the Δhfq mutants, her lab notes had swapped the two strains in some places. Looking at the data, it also seems reasonable that what I’ve been calling Δhfq murE749 is actually Δhfq sxy-1:



I’ll have to experimentally verify this by using a restriction endonuclease (Mnl I) that has an additional cleavage site in the murE749 mutant. It’s nice to know that this will probably answer a lot of questions that I have, but I am now left with no leads to identify where the Hfq effect on competence occurs. Science is a harsh mistress.

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