x1 = pRB
x2 = pRBp
x3 = pRBpp
x4 = E2F
x5 = E2Fp
x6 = pRBc1
x7 = pRBc2
x8 = Cd
x9 = Mdi
x10 = Md
x11 = Mdp27
x12 = Ce
x13 = Mei
x14 = Me
x15 = Skp2
x16 = Mep27
x17 = Pei
x18 = Pe
x19 = Ca
x20 = Mai
x21 = Ma
x22 = Map27
x23 = p27
x24 = p27p
x25 = Cdh1i
x26 = Cdh1a
x27 = Pai
x28 = Pa
x29 = Cb
x30 = Mbi
x31 = Mb
x32 = Mbp27
x33 = Cdc20i
x34 = Cdc20a
x35 = Pbi
x36 = Pb
x37 = Wee1
x38 = Wee1p
x39 = Pol
x40 = Cdc45
x41 = Primer
x42 = Chk1
x43 = ATR
x44 = AP1
x45 = Mw