FIG. 5.

Ctf4p and Ctf18p are chromatin associated. Cells grown to early log phase in rich medium were arrested in α-factor (G₁), HU (S), or nocadozole (M) for 2.5 h. (A) Ctf18p-9myc (in YJH40.4) was detected using indirect immunofluorescence on chromosome spreads. For comparison, an untagged control strain (YPH277) in log phase is shown in the top row. Drug-induced arrests were verified by flow cytometry as shown. (B) Ctf4p-9myc (YJH38) cells were similarly analyzed. (C) Chromatin pellet fractions from cells containing Ctf18p-9myc (YJH40.4), Ctf4p-9myc (YJH38), and Orc3p (YJH62.6) were generated from arrested cell populations as above and analyzed by Western blotting. Similar results were obtained for Ctf18p-9myc and Ctf4p-9myc in four independent experiments. Results for Orc3p are consistent with previous data from Liang and Stillman (57). In these experiments, a pellet-to-supernatant cell equivalent loading ratio of 4:1 was used.