Hello again!! Thanks for still putting up with my writings ^^
I would to continue, just a little a bit, about the whole DSBR conversation. Completing the earlier 2 pathways, the last one is called the Microhomology Mediated End-Joining (MMEJ), or sometimes it's called as alternative end-joining (altNHEJ). .
In some occasion, some polypeptides might covalently attached to the end of a broken DNA. Consequently, these DNA ends couldn't be bound by the Ku70/80 complex. and be repaired in the usual NHEJ pathway. As an alternative (thus, it's called alternative end-joining/altNHEJ), these ends will follow a Ku-independent repair pathway.
Basically, in this pathway, the blocked end will be removed by nucleolytic process, and one strand of the end will be resected (or digested or deleted or removed) until "they" find a small region (5-20kb) which is compliment (or homologue) to the other end of the broken strand. The broken ends are stabilized by the base-pairing. That's why it's called "Microhomology". After the base-pairing, the "flapping" (basically the leftovers of each strand) are removed, and the ligation occurs.
Well, in the end, at least 2 of the 3 pathways will definitely make a mutation to the DNA sequence. This is a solid prove by nature that "To prevent a further damage, there is always something in return to be sacrificed" (Oh my goodness!! How wise am I in this post!!! >o<)
As a comparison, you can check on a brief diagram below.
Ow, as a note..every picture I put in the posts is directly linked to the original paper, if you click it. Just in case you are curious to learn further ^^
So, Happy Friday everybody!! It might a wonderful TGIF for some people, and just another Friday for another...BUT!! Thanks for reading!!
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