Removal of RNA primer and dissociation of RPA and Dna2 from the C-strand

The DNA2 endonuclease removes the initiator RNA along with several downstream deoxyribonucleotides. The cleavage of the single-stranded RNA substrate results in the disassembly of RPA and DNA2. The current data for the role of the DNA2 endonuclease has been derived from studies of yeast (Budd et al. 2000, Bae et al. 2001) and Xenopus DNA2 (Liu et al. 2000, Liao et al. 2008). DNA2-mediated cleavage of G-quadruplexes (G4), DNA structures commonly formed by polyguanine-rich telomeric DNA sequences, is necessary for completion of telomeric DNA synthesis (Masuda-Sasa et al. 2008, Lin et al. 2013).

DNA2内切酶移除启动RNA及其下游的数个脱氧核糖核苷酸。对单链RNA底物的切割导致RPA和DNA2的解聚。目前关于DNA2内切酶作用的数据来源于对酵母（Budd等，2000年，Bae等，2001年）及非洲爪蟾DNA2（Liu等，2000年，Liao等，2008年）的研究。DNA2介导的G-四链体（G4）切割，即由富含鸟嘌呤的端粒DNA序列形成的DNA结构，对于端粒DNA合成的完成至关重要（Masuda-Sasa等，2008年，Lin等，2013年）。