The SOS response is a last ditch effort for survival by a pathogen when subjected to DNA damage. It involves the activation of numerous genes that are normally repressed causing accelerated mutation. This is all achieved through the use of DNA polymerases that are naturally more error prone and so mutate the genetic code far more quickly. You can find out all about the mechanism of the SOS response here.
A recent study has shown that LexA, the master switch for the SOS response, is involved in controlling effector proteins crucial for Enteropathogenic Escherichia coli (EPEC), the main cause of watery diarrhea, to attach to the intestinal wall and then secrete proteins into the host cell. Why is this important? Because it can be seen that there is a coordinated response by this pathogen to increase its chances of survival both by mutating to protect itself from any barrage the body or antibiotics can through at it, as well trying to increase its chances of infection by producing more toxic compounds. Now that is one smart (and scary) bacterium!
Posted by: Connor Skennerton (41192373)
References:
- Jay L Mellies, Kenneth R Haack, and Derek C Galligan (2007). €œSOS regulation of the type III secretion system of enteropathogenic Escherichia coli, Journal of bacteriology 189, no. 7: 2863-72.
- Ryan T Cirz et al. (2005) €œInhibition of Mutation and Combating the Evolution of Antibiotic Resistance,€ PLoS Biology 3, no. 6: e176, http://dx.doi.org/10.1371%2Fjournal.pbio.0030176.
