The DNase activity of an endoplasmic reticulum nuclease and its effect on DNA synthesis in vitro
Abstract:
An endoplasmic reticulum nuclease which was isolated previously in this laboratory from rat liver ( Kouidou et al. (1981) Eur.J. Bioch . 120, 9-14) was found to degrade linear and circular single stranded DNA but not double stranded DNA. The DNA fragments resulting from this cleavage were longer than 20 nucleotides. In addition the nuclease was found to improve the efficiency of DNA template used by DNA polymerase I in DNA synthesis in vitro. The results were the same whether incubation of the template with the nuclease was prior to addition of DNA polymerase I or simultaneously with polymerization. When nuclease was added after the completion of polymerization by DNA polymerase I it was ineffective unless the product was denatured. These data further corroborate the observation that double stranded DNA is not cleaved by this enzyme.
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