摘要：

A partially single-stranded DNA, prepared by limited digestion of each strand with exonuclease III, can be restored to its native, fully double-stranded structure by Escherichia coli DNA polymerase. The rate of synthesis observed in the repair of such a partially degraded primer in the polymerase system is faster than that seen with a native DNA. The newly synthesized DNA is covalently attached to the primer. The fully repaired DNA resembles the original native DNA as judged by its appearance in electron micrographs, CsCl density-gradient analysis, denaturability and genetic activity. DNA synthesis which follows the repair phase produces a structure that is not covalently linked to the primer and resembles, in its nondenaturability, branched appearance, and lack of genetic activity, the product obtained with a native DNA primer (Schildkraut, Richardson & Kornberg, 1964).

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