A 25 kDa protein called geminin inhibits DNA replication and is degraded during mitosis. Geminin contains a destruction box sequence and is ubiquitinated by the anaphase-promoting complex (APC). In synchronized HeLa cells, geminin is absent during G1 phase, accumulates during S, G2, and M phases, and is degraded at the metaphase-anaphase transition. Geminin inhibits DNA replication by preventing the incorporation of the MCM complex into the prereplication complex (pre-RC). The degradation of geminin at the metaphase-anaphase transition allows DNA replication in the next cell cycle. Geminin is mitotically degraded by the APC pathway. Xenopus egg extracts demonstrate that geminin is degraded specifically during mitosis. Geminin contains a destruction box sequence near its amino terminus, which is necessary for its degradation. When geminin is removed from cell extracts, DNA replication proceeds normally. Geminin is a nuclear protein and is degraded in vivo at the metaphase-anaphase transition. Geminin inhibits DNA replication by preventing the assembly of the pre-RC. Geminin inhibits the initiation of DNA replication but not elongation or ongoing synthesis. Geminin inhibits the formation of the pre-RC by preventing the incorporation of the MCM complex into the pre-RC. Geminin is a nuclear protein that is degraded by the APC pathway during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitA 25 kDa protein called geminin inhibits DNA replication and is degraded during mitosis. Geminin contains a destruction box sequence and is ubiquitinated by the anaphase-promoting complex (APC). In synchronized HeLa cells, geminin is absent during G1 phase, accumulates during S, G2, and M phases, and is degraded at the metaphase-anaphase transition. Geminin inhibits DNA replication by preventing the incorporation of the MCM complex into the prereplication complex (pre-RC). The degradation of geminin at the metaphase-anaphase transition allows DNA replication in the next cell cycle. Geminin is mitotically degraded by the APC pathway. Xenopus egg extracts demonstrate that geminin is degraded specifically during mitosis. Geminin contains a destruction box sequence near its amino terminus, which is necessary for its degradation. When geminin is removed from cell extracts, DNA replication proceeds normally. Geminin is a nuclear protein and is degraded in vivo at the metaphase-anaphase transition. Geminin inhibits DNA replication by preventing the assembly of the pre-RC. Geminin inhibits the initiation of DNA replication but not elongation or ongoing synthesis. Geminin inhibits the formation of the pre-RC by preventing the incorporation of the MCM complex into the pre-RC. Geminin is a nuclear protein that is degraded by the APC pathway during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the initiation of DNA synthesis. Geminin is a nuclear protein that is degraded during mitosis. Geminin inhibits DNA replication by preventing the formation of the pre-RC. Geminin is a nuclear protein that is degraded during mit