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Restriction enzymes cut the DNA of bacteriophages. Have bacteriophages evolved any mechanism to protect themselves from it ?

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up vote 3 down vote accepted

I guess you are talking about the restriction modification system, not restriction enzymes in general (which are used a lot in the lab, for example). If so, this paper might help answer your question.

I have not read through it totally, but at least some viruses trigger the downregulation of restriction enzymes to make them cleaving their DNA less likely. Restriction enyzmes are also quite selective for the site they cut at, so single nucleotide changes at this site, might, if the phage is lucky, not change the function of the encoded gene, but keep the restriction enzyme from binding (and thus cleaving) at that site. Mutating helps a lot. And it is fast in those little critters.

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One of my friends said that they have ligase to join their fragments again , but that doesn't seem correct because then the bacteria could again use restriction enzyme to cut it. What is your opinion ? – biogirl Aug 14 '13 at 9:19
A biological system is always fluent. There are several possibilities to "kit" the DNA, especially ligase. But then, as you said, the DNA would be cut again. The main point for the bacterium is, to prevent it from being stable enough to be transcribed. – skymningen Aug 21 '13 at 6:11
Do you know an actual virus that does so?(I tried googling it but couldn't get anything :) ) – biogirl Aug 21 '13 at 6:18
In the wikipedia article for DNA ligase you'll find an example of a bacteriophage ligase. Also, even the bacterias own ligase could ligate the foreign DNA. An enzyme has (more or less) specific binding sites, but it does not recognise anything beside that. Ligases need co-factors to bind and ligate, but the cofactors for the bacterium ligase of course will be present. – skymningen Aug 21 '13 at 6:26
That's interesting ! Thank you :) – biogirl Aug 21 '13 at 6:28

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