Can bacteria conduct do dark repair (excision repair)?

Question

Can bacteria conduct perform dark repair (excision repair)? (Specifically e. coli and b. subtilis)

Answer 1

Yes, bacteria (see attached article for info on E.coli) can repair thymine dimers (and other base mutations) by excision repair (aka dark repair).

There are two types of excision repairs-

1.Base Excision repair- This only removes a defective base (by specific enzymes called glycosylases)

2.Nucleotide excision repair- It removes a region surrounding the mis-incorporated nucleotide with Uvr proteins (viz. Uvr A, B, C, D). Again, see attached article for function of each protein. http://trishul.sci.gu.edu.au/courses/ss1...

I think that excision repair is present in all pro & eukaryotes (different set of proteins involved though).

B. subtilis also has a specific system of repair called Non- Homologous End Joining (NHEJ). It is a backup sytem to repair double stranded breaks in DNA. It is commonly seen in yeasts (i.e. eukaryotes) but infrequently seen in bacteria. And, it is found in B. subtilis spores.