6786 Nucleic Acids Research, 2012, Vol. 40, No. 14 during lagging-strand DNA replication. Genes Dev., 18, 2764–2773. 43. Rossi,M.L., Pike,J.E., Wang,W., Burgers,P.M., Campbell,J.L. and Bambara,R.A. (2008) Pif1 helicase directs eukaryotic Okazaki fragments toward the two-nuclease cleavage pathway for primer removal. J. Biol. Chem., 283, 27483–27493. 44. Jin,Y.H., Ayyagari,R., Resnick,M.A., Gordenin,D.A. and Burgers,P.M. (2003) Okazaki fragment maturation in yeast. II. Cooperation between the polymerase and 30-50-exonuclease activities of Pol delta in the creation of a ligatable nick. J. Biol. Chem., 278, 1626–1633. 45. Tsurimoto,T. and Stillman,B. (1991) Replication factors required for SV40 DNA replication in vitro. II. Switching of DNA polymerase alpha and delta during initiation of leading and lagging strand synthesis. J. Biol. Chem., 266, 1961–1968. 46. Mozzherin,D.J., Tan,C.K., Downey,K.M. and Fisher,P.A. (1999) Architecture of the active DNA polymerase delta.proliferating cell nuclear antigen.template-primer complex. J. Biol. Chem., 274, 19862–19867. 47. Tan,C.K., Castillo,C., So,A.G. and Downey,K.M. (1986) An auxiliary protein for DNA polymerase-delta from fetal calf thymus. J. Biol. Chem., 261, 12310–12316. 48. Prelich,G., Tan,C.K., Kostura,M., Mathews,M.B., So,A.G., Downey,K.M. and Stillman,B. (1987) Functional identity of proliferating cell nuclear antigen and a DNA polymerase-delta auxiliary protein. Nature, 326, 517–520. 49. Beattie,T.R. and Bell,S.D. (2012) Coordination of multiple enzyme activities by a single PCNA in archaeal Okazaki fragment maturation. EMBO J., 31, 1556–1567. 50. Jonsson,Z.O., Hindges,R. and Hubscher,U. (1998) Regulation of DNA replication and repair proteins through interaction with the front side of proliferating cell nuclear antigen. EMBO J., 17, 2412–2425. 51. Maga,G. and Hubscher,U. (2003) Proliferating cell nuclear antigen (PCNA): a dancer with many partners. J. Cell Sci., 116, 3051–3060. 52. Henry,R.A., Balakrishnan,L., Ying-Lin,S.T., Campbell,J.L. and Bambara,R.A. (2010) Components of the secondary pathway stimulate the primary pathway of eukaryotic Okazaki fragment processing. J. Biol. Chem., 285, 28496–28505. 53. Zheng,L. and Shen,B. (2011) Okazaki fragment maturation: nucleases take centre stage. J. Mol. Cell Biol., 3, 23–30. 54. Hasan,S., Stucki,M., Hassa,P.O., Imhof,R., Gehrig,P., Hunziker,P., Hubscher,U. and Hottiger,M.O. (2001) Regulation of human ﬂap endonuclease-1 activity by acetylation through the transcriptional coactivator p300. Mol. Cell, 7, 1221–1231. 55. Masuda-Sasa,T., Polaczek,P. and Campbell,J.L. (2006) Single strand annealing and ATP-independent strand exchange activities of yeast and human DNA2: possible role in Okazaki fragment maturation. J. Biol. Chem., 281, 38555–38564.