cell cycle One chromosome, live C1 Firing program pick a genotype, run it Click an origin on the chromosome to show it here. Once it fires, the camera follows a fork.
origin left fork right fork centromere
nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 6 4 7 2 5 3 Cdc45 G I N S ARS 2 5 3 6 4 7 NSD NSD P P P P P P 1 6 5 4 3 2 Cdc6 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 6 4 7 2 5 3 Cdc45 G I N S ARS 2 5 3 6 4 7 NSD NSD P P P P P P 1 6 5 4 3 2 Cdc6 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha nuc nuc nuc nuc nuc nuc 2 5 3 Cdc45 G I N S 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA Ddc2 Mec1 no Rad53 Rad53 Rad53 P P Exo1 nuc nuc nuc nuc nuc nuc 6 4 7 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA Ddc2 Mec1 no Rad53 Rad53 Rad53 P P Exo1 nuc nuc nuc nuc nuc nuc 2 5 3 Cdc45 G I N S 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA Ddc2 Mec1 no Rad53 Rad53 Rad53 P P Exo1 nuc nuc nuc nuc nuc nuc 6 4 7 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA RPA Ddc2 Mec1 no Rad53 Rad53 Rad53 P P Exo1 nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 2 5 3 Cdc45 G I N S ARS 2 5 3 6 4 7 NSD NSD P P P P P P 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha Rrm3 nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 6 4 7 ARS 2 5 3 6 4 7 NSD NSD P P P P P P 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha Rrm3 nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 2 5 3 Cdc45 G I N S ARS 2 5 3 6 4 7 NSD NSD P P P P P P 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha Rrm3 nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 6 4 7 ARS 2 5 3 6 4 7 NSD NSD P P P P P P 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha Rrm3 RPA RPA RPA RPA RPA RPA RPA RPA stalled ends nuc nuc nuc nuc nuc CEN (CDE I, II, III) Cse4 Ctf19 (COMA) Mtw1 (MIND) Ndc80 Dam1 Cse4 Ctf19 (COMA) Mtw1 (MIND) Ndc80 Dam1 cohesin CMG CMG Exo1 Exo1 not to scale along the DNA 6 4 7 2 5 3 Cdc45 G I N S 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha SCF-Dia2 Cdc48 SCF-Dia2 Cdc48 6 4 7 2 5 3 Cdc45 G I N S 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha SCF-Dia2 Cdc48 SCF-Dia2 Cdc48 nuc nuc nuc nuc 1 6 5 4 3 2 Cdc45 6 4 7 2 5 3 ARS Sld3 Sld7 Cdc45 2 5 3 6 4 7 NSD NSD P P P P P P the clasp is cut to the bare pair and its cleft to the NSD mark one arm to each hexamer, Cdc45 partly seated on Mcm5 Origin state Specification Licensing Activation Fork Sld3 and Sld7 are drawn as one clasp taking the pair from underneath. Its floor is cut from the profile the hexamers are drawn with, and one star cleft in it takes the mark on the displaced NSD, so the clasp reads the mark and rests on the pair in one fit. The seated NSD would stand where that floor goes. Cdc45 rides the arms partly seated at the Mcm2-Mcm5 gate, on Mcm5 and tilted off Mcm2, until GINS completes the seat. nuc nuc nuc nuc 1 6 5 4 3 2 Cdc45 6 4 7 2 5 3 ARS S-CDK Sld3 Sld7 P Cdc45 2 5 3 6 4 7 NSD NSD P P P P P P Sld2 P no fixed order with DDK Origin state Specification Licensing Activation Fork The kinase travels to each of its two substrates, and the frame each mark arrives carries a yellow arrow from the burst to it. The Sld3 that S-CDK marks is the one already on the origin, because Sld3 loads without CDK activity and CDK cannot be what put it there. A mark a protein carries sits on its shoulder and a mark it reads sits in a cleft, so one shape no longer says both. nuc nuc nuc nuc 1 6 5 4 3 2 Cdc45 6 4 7 2 5 3 6 4 7 2 5 3 Cdc45 G I N S Pol eps ARS Dpb11 Sld2 P G I N S Pol eps G I N S Pol eps Sld3 Sld7 P Cdc45 2 5 3 6 4 7 NSD NSD P P P P P P 2 5 3 Cdc45 G I N S Pol eps 6 4 7 ATP ADP exchanged for ATP Origin state Specification Licensing Activation Fork Cdc45 opens the panel partly seated and lies flat across the Mcm2-Mcm5 gate in the frame GINS arrives, one seal in front of the DNA and one behind it, on the face of each hexamer that carries its gate. Pol epsilon comes in with GINS and stays beside it, which makes each helicase CMGE. The pair splits in that frame into two CMGs whose teeth meet without interleaving, and Sld3 leaves after the split. Dpb11 is drawn with all three cuts filled; the star cut on its end face takes the S-CDK mark on Sld3. nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 Cdc45 G I N S Pol eps ARS 2 5 3 Cdc45 G I N S Pol eps 6 4 7 fork fork Mcm10 ATP ADP exchanged for ATP ATP ATP hydrolysis Origin state Specification Licensing Activation Fork The two CMGs enter this panel split but still facing each other. Mcm10 arrives over their N faces, melting starts in the middle of the pair in the next frame, and the two CMGs separate completely as the region extrudes, which is when Mcm10 is released. nuc nuc nuc nuc 1 6 5 4 3 2 6 4 7 2 5 3 Cdc45 G I N S ARS 2 5 3 Cdc45 G I N S fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha 6 4 7 fork RPA Tof1-Csm3 Mrc1 P Pol eps Ctf4 Pol alpha ATP ATP hydrolysis Origin state Specification Licensing Activation Fork New DNA is drawn on the substrate as a fourth strand state, so what the polymerases do is on the page and not in this note. The leading template is the top strand on the left of the origin and the bottom strand on the right, which is why the two forks are mirror images. Leading pieces appear as their own position opens; a lagging fragment is primed where the fork is and fills backward, so bare template is left behind each fork and the fragment in progress is unfinished when the fork leaves the frame. The camera is fixed and the two forks leave the frame. No camera position holds two objects moving apart at a constant rate. ORC does not move and does not go: it holds the ARS while the forks travel out past it, and it stays bound through S and G2/M, which is where the budding yeast initiator differs from the metazoan one. Sld3 Sld7 Dpb11 Sld2 P set held in the tray: Rad53 marked Sld3 Sld3 Sld7 Dpb11 Sld2 no free set yet RNR makes the dNTPs the forks draw on HU Rad53, via Dun1: more RNR 0 of 20 marks DDK P 0 DDK Rif1-PP1 0 Rif1-PP1 Origin close-up: L1