FANCI-FANCD2 stabilizes the RAD51-DNA complex by binding RAD51 and protects the 5'-DNA end.

The FANCI-FANCD2 (I-D) complex is considered to work with RAD51 to protect the damaged DNA in the stalled replication fork. However, the means by which this DNA protection is accomplished have remained elusive. In the present study, we found that the I-D complex directly binds to RAD51, and stabilizes the RAD51-DNA filament.

Expression and purification of human FANCI and FANCD2 using Escherichia coli cells.

The DNA interstrand crosslink (ICL) is an extremely deleterious DNA lesion that covalently crosslinks complementary strands and prevents the strand-separation reaction. In higher eukaryotes, the Fanconi anemia proteins, FANCI and FANCD2, form a heterodimer and play essential roles in ICL repair. Human FANCI and FANCD2 are large proteins with molecular masses of 149kDa and 164kDa, respectively, and were reportedly purified using a baculovirus expression system with insect cells.