“…In budding yeast, Sld3 and Cdc45 associate with early-firing origins early in G1 phase, whereas they do not associate with late-firing origins until approximately the time these origins fire in S phase (Aparicio et al, 1997;Gambus et al, 2006;Kamimura et al, 2001). Recent experiments suggest that the amount of firing factors present determines both the efficiency of origin firing and its timing (Krasinska et al, 2008;Mantiero et al, 2011;Patel et al, 2008;Wu and Nurse, 2009). The amounts of Sld2, Sld3, Sld7, Dpb11, Cdc45 and Dbf4 have been quantified in budding yeast, and they are well below the number of loaded Mcm2-7 helicases (Mantiero et al, 2011;.…”