Figure 7. Formation and repair of DSB arising when replication forks encounter damage.

Figure 7

Formation and repair of DSB arising when replication forks encounter damage. (A) Arrest of the replication fork. (B) Fork collapse and DSB generation upon the encounter of the replication fork with a preexisting nick or gap. (C) Formation of a Holliday junction (HJ) at the site of a broken fork. (D) Replication fork encounters a leading strand lesion, designated “X”, resulting in the generation of single-stranded DNA. (E) Fork regression (reversal) by branch migration generates a four-stranded chicken-foot structure; extension of the leading strand may occur in the sequence corresponding to that of the site of the lesion. (F) Resolution of the HJ by resolvase, resulting in an incompletely replicated chromosome. (G) Branch migration resets the replication fork with the lesion either present or absent.

From: Origin, Recognition, Signaling and Repair of DNA Double-Strand Breaks in Mammalian Cells

Cover of Madame Curie Bioscience Database
Madame Curie Bioscience Database [Internet].
Austin (TX): Landes Bioscience; 2000-2013.
Copyright © 2000-2013, Landes Bioscience.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.