Molecular and General Genetics MGG

, Volume 154, Issue 3, pp 263–267 | Cite as

RNA-linked nascent DNA pieces in T7 phage-infectedEscherichia coli cells

I. Role of gene 6 exonuclease in removal of the linked RNA
  • Kazuo Shinozaki
  • Tuneko Okazaki


The presence of RNA-linked nascent DNA pieces in T7 phage-infectedEscherichia coli cells has been shown by the selective degradation of the 5′-hydroxyl-terminated nascent DNA, produced by alkali or RNase treatment, with spleen exonuclease. At 43°C, the proportion of RNA-linked DNA pieces in nascent short DNA is 50 to 60% in T7ts136 (ts mutant of gene 6) phage-infectedE. coli, whereas that in T7 wild-type phage-infected cells is less than 6%. Joining of the nascent pieces is greatly retarded in T7ts136-infectedE. coli temperature sensitivepolA mutants at 43° C. These results suggest that gene 6 exonuclease plays a role in removal of the linked RNA during the discontinuous replication of T7 DNA.


Coli Cell Coli Temperature RNase Treatment Selective Degradation 
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  1. Fröhlich, B., Powling, A., Knippers, R.: Formation of concatemeric DNA in bacteriophage T7-infected bacteria. Virology65, 455–468 (1975)Google Scholar
  2. Grippo, P., Richardson, C.C.: Deoxyribonucleic acid polymerase of bacteriophage T7. J. biol. Chem.246, 6867–6873 (1971)Google Scholar
  3. Hinkle, D.C., Richardson, C.C.: Bacteriophage T7 deoxynucleic acid replication in vitro. J. biol. Chem.249, 2974–2984 (1974)Google Scholar
  4. Kerr, C., Sadowski, P.D.: Gene 6 exonuclease of bacteriophage T7. I. Purification and properties of the enzyme. J. biol. Chem.247, 305–310 (1972a)Google Scholar
  5. Kerr, C., Sadowski, P.D.: Gene 6 exonuclease of bacteriophage T7. II. Mechanism of the reaction. J. biol. Chem.247, 311–318 (1972b)Google Scholar
  6. Kolodner, R., Richardson, C.C.: Replication of duplex DNA by bacteriophage T7 DNA polymerase and gene 4 protein is accompanied by hydrolysis of nucleoside 5′-triphosphates. Proc. nat. Acad. Sci. (Wash.)74, 1525–1529 (1977)Google Scholar
  7. Kurosawa, Y., Ogawa, T., Hirose, S., Okazaki, T., Okazaki, R.: Mechanism of DNA chain growth. XV. RNA-linked nascent DNA pieces inEscherichia coli strains assayed with spleen exonuclease. J. molec. Biol.96, 653–664 (1975)Google Scholar
  8. Mark, D.F., Richardson, C.C.:Escherichia coli thioredoxin. A subunit of bacteriophage T7 DNA polymerase. Proc. nat. Acad. Sci. (Wash.)73, 780–784 (1976)Google Scholar
  9. Masamune, Y., Frenkel, G.D., Richardson, C.C.: A mutant of bacteriophage T7 deficient in polynucleotide ligase. J. biol. Chem.246, 6874–6879 (1971)Google Scholar
  10. Miller, R.C., Lee, M.: The role of bacteriophage T7 exonuclease (gene 6) in genetic recombination and production of concatemers. J. molec. Biol.101, 223–234 (1976)Google Scholar
  11. Ogawa, T., Hirose, S., Okazaki, T., Okazaki, R.: Mechanism of DNA chain growth. XVI. Analyses of RNA-linked DNA pieces inEscherichia coli with polynucleotide kinase. J. molec. Biol.112, 121–140 (1977)Google Scholar
  12. Okazaki, R.: Short-chain intermediates in DNA replication. DNA replication (Wickner, R.B. ed.), pp. 1–32. New York: Marcel Dekker 1974Google Scholar
  13. Okazaki, R., Okazaki, T., Hirose, S., Sugino, A., Ogawa, T., Kurosawa, Y., Shinozaki, K., Tamanoi, F., Seki, T., Machida, Y., Fujiyama, A., Kohara, Y.: Discontinuous replication in prokaryotic systems. DNA synthesis and its regulation (Goulian, M.D., Hanawalt, P. eds.), pp. 832–862. California: W.A. Benjamin 1975Google Scholar
  14. Powling, A., Knippers, R.: Some functions involved in bacteriophage T7 genetic recombination. Molec. gen. Genet.134, 173–180 (1974)Google Scholar
  15. Sadowski, P.D., Kerr, C.: Degradation ofEscherichia coli B deoxyribonucleic acid after infection with deoxyribonucleic acid-defective amber mutants of bacteriophage T7. J. Virol.6, 149–155 (1970)Google Scholar
  16. Scherzinger, E., Klotz, G.: Studies on bacteriophage T7 DNA synthesis in vitro. Molec. gen. Genet.141, 233–249 (1975)Google Scholar
  17. Scherzinger, E., Lanka, E., Morelli, G., Seiffert, D., Yuki, A.: Bacteriophage T7 induced DNA-priming protein. A novel enzyme involved in DNA replication. Europ. J. Biochem.72, 543–558 (1977)Google Scholar
  18. Sternglanz, R., Wang, H.F., Donegan, J.J.: Evidence that both growing DNA chains at a replication fork are synthesized discontinuously. Biochemistry15, 1838–1843 (1976)Google Scholar
  19. Strätling, W., Ferdinand, F.J., Krause, E., Knippers, R.: Bacteriophage T7-DNA replication in vitro: An experimental system. Europ. J. Biochem.38, 160–169 (1973)Google Scholar
  20. Studier, F.W.: The genetics and physiology of bacteriophage T7. Virology39, 562–574 (1969)Google Scholar
  21. Studier, F.W.: Bacteriophage T7. Science176, 367–376 (1972)Google Scholar
  22. Type, B-K., Nyman, P-O., Lehman, I.R., Hochhauser, S., Wiess, B: Transient accumulation of Okazaki fragments as a result of uracil incorporation into nscent DNA. Proc. nat. Acad. Sci. (Wash.)74, 154–157 (1977)Google Scholar

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Kazuo Shinozaki
    • 1
  • Tuneko Okazaki
    • 1
  1. 1.Institute of Molecular Biology, Faculty of ScienceNagoya UniversityNagoyaJapan

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