Figure 4. CSN-CRL4^CDT2 contains both CUL4A and CUL4B in S-phase.

(A) Cell cycle distribution of HeLa cells transfected with the indicated siRNAs was analyzed by DNA content flow cytometry detection. A representative FACS profile is shown. Percentage of cells in G₂ with a 4C or >4C DNA content were calculate by Cell Quest software. (B) (C) (D) HeLa cells were synchronized by DTB and, where indicated, transfected with myc control or myc-CUL4B vectors in between the two thymidine blocks. Cells were harvested at 2.5 hrs after DTB release and total cell protein extracts were prepared. Cell lysate was subjected to immunoprecipitation with serum as control or with the indicated antibodies. Immunoprecipitates and cells lysates were immunoblotted with the indicated antibodies. (D) Both low and high exposure films are shown. HMW is High Molecular weight; LMW is low molecular weight.