title: Periodic DNA synthesis in cell-free extracts of Xenopus eggs.
abstract: Cell-free extracts prepared from unfertilized eggs of Xenopus laevis support DNA synthesis on sperm pronuclei. Continuous labelling studies using [3H]dCTP and pulse labelling studies using [32P]dCTP demonstrate that synthesis occurs in short bursts of 40 min, which are punctuated by periods of 20-40 min during which no synthesis occurs. Density substitution experiments using bromodeoxyuridine demonstrate that this synthesis involves the initiation of replication and reveals that re-initiation events can occur following multiple bursts of replication. The periodic properties of these extracts are sensitive to protein synthesis inhibitors.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002474:Cell-Free System; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication; D003854:Deoxyribonucleotides / Q000378:metabolism; D005260:Female; D008297:Male; D009865:Oocytes / Q000502:physiology*; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D003854:Deoxyribonucleotides; D004247:DNA