title: Circular single stranded phage M13-DNA as a template for DNA synthesis in protein extracts from Xenopus laevis eggs: evidence for a eukaryotic DNA priming activity.
abstract: Unfractionated protein extracts from activated Xenopus laevis eggs contain all functions required for the chain elongation reactions in replicative DNA synthesis (A.Richter, B. Otto and R.Knippers, 1981, Nucl.Ac.Res. 9, 3793-3807). In order to further explore the DNA synthesizing capacity of this in vitro system and to obtain information on the DNA priming activity in these extracts single stranded phage M13-DNA was used as template for in vitro DNA synthesis. The main results of this investigation are: (i) single stranded circular template DNA is converted to a double stranded DNA form in an alpha-amanitin-insensitive reaction which is absolutely dependent on ribonucleoside triphosphates; (ii) the in vitro synthesized complementary strands are DNA fragments of 1000-2000 nucleotides lengths; (iii) the DNA primase activity copurifies through several column steps and sucrose gradient centrifugation with a DNA polymerase alpha. These activities may therefore be closely associated in a quarternary enzyme complex.
mesh_terms: D000818:Animals; D003090:Coliphages / Q000235:genetics*; D019915:DNA Primase; D004261:DNA Replication; D004270:DNA, Circular / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics*; D004527:Egg Proteins; D005260:Female; D007700:Kinetics; D009865:Oocytes / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D013698:Templates, Genetic; D014779:Virus Replication; D014981:Xenopus
chemical_list: D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004527:Egg Proteins; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases