Figure 2.

Reconstitution of XCdc7/XDbf4. (A) Whole Xenopus egg extract and chromatin isolated from interphase extract were immunoblotted with XDbf4, XCdc7 and XMcm7 antibodies. (B) Interphase Xenopus egg extracts were immunodepleted with antibodies against XDbf4 (XDbf4-) or XCdc7 (XCdc7-) antibodies or with an equal quantity of non-immune antibodies (NI-). Depleted extracts were immunoblotted with XDbf4, XCdc7 or XMcm7 antibodies. (C) Interphase extracts depleted with either XCdc7 antibodies or non-immune antibodies were supplemented with [α-³²P]dATP and incubated for 2 hr with Xenopus sperm nuclei or licensed interphase chromatin, in the presence or absence of recombinant XDbf4 and/or XCdc7. After incubation, DNA synthesis was measured, and expressed as a percentage of that occurring in control extract.