Biopolymers and cell. 1985. Volume 1. № 5. 234 - 241

D. O. Ataeva, K. A. Marlyev, P. K. Kullyev, V. S. Mikhailov

SYNTHESIS ON SINGLE-STRANDED CIRCULAR PHAGE M13 DNA BY DNA POLYMERASE OF NUCLEAR SILKWORM POLYHEDROSIS VIRUS

Summary

    A virus-induced DNA polymerase (B. m. NPV polymerase) was purified from the silk¬worm Bombyx mori pupae infected with nuclear polyhedrosis virus (B. m. NPV). NPV polymerase is a polypeptide with a molecular weight of 136 kDa and a sedimentation coefficient of 6.3 S. As a template, B. m. NPV polymerase prefers polydeoxynucleotide poly(dA) with a primer (dT)io and is inactive when using poly(A). Partially purified B. m. NPV polymerase is active on the single-standed circular phage M13 DNA in the absence of a primer. The ability to utilize phage M13 DNA as a template is due to the presence of a Mg2+-dependent endonuclease specific to double-stranded DNA in the preparations of B. m. NPV polymerase. The endonuclease exists in the B. m. NPV polymerase preparations after ammonium sulphate fractionation, phosphocellulose and hydroxyapatite chromatography but may be separated from B. m. NPV polymerase by glycerol gradient ultracentrifugation in the presence of 200 rnM potassium phosphate. At the lower salt concentrations B. m. NPV polymerase and the endonuclease reveal a tendency to aggregation.