MGY377H1 Midterm: Study notes for midterm
26 Dec 2011
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Document Summary
Horizontal lateral gene transfer plays major role in prokaryotic evolution. The five major pathogenicity islands of salmonella typhimurium are all more at rich than the rest of the genome. Binds dna with little sequence specificity prefers at rich dna. Hns has poor dna binding protein but it exhibits cooperative binding behaviour: can nucleate at a high-affinity site and polymerize along at rich tracts to generate extended footprints on dna templates. Regulates large number of genes obtained by horizontal transfer. Hns can discriminate on the basis of at content and length. Characteristic gc-content of the bacterial genome can be exploited to recognize and silence alien sequences. Provides common framework for how most novel genes are regulated after being taken up by the bacterial cell without compromising its genomic and regulatory integrity. Has allowed bacteria to simultaneously acquire and protect themselves from foreign dna. Alternation of local structure due to alternative sigma factors.
