Replication Protein A3 (RPA3)

The RPA3 gene has a 692-basepair sequence with an open reading frame encoding a protein of 121 amino acids. The deduced amino acid sequence showed only limited similarity to the small subunit of yeast RPA. See also RPA1 and RPA2.

In vitro, RPA stimulates the binding of ATRIP to single-stranded DNA. The binding of ATRIP to RPA-coated single-stranded DNA enables the ATR-ATRIP complex to associate with DNA and stimulates phosphorylation of the RAD17 protein that is bound to DNA. Furthermore, Ddc2, the budding yeast homolog of ATRIP, is specifically recruited to double-stranded DNA breaks in an RPA-dependent manner. A checkpoint-deficient mutant of RPA, rfa1-t11, is defective for recruiting Ddc2 to single-stranded DNA both in vivo and in vitro.