Abstract
The DNA polymerase of bacteriophage T4 is a multifunctional enzyme that harbors DNA-binding, DNA-synthesizing and exonucleolytic activities. We have cloned in bacterial plasmids about 99% of the structural gene for this enzyme (T4 gene 43). The gene was cloned in six contiguous 5'-terminal DNA fragments that defined seven intragenic mapping regions. Escherichia coli hosts harboring recombinant plasmids carrying the gene 43 subsegments were used in marker-rescue experiments that assigned a large number of ts and nonsense polymerase mutations to different physical domains of the structural gene. Conspicuously, only one missense mutation in a large collection of mutants mapped in the 5'-terminal 450 base-pair segment of the approximately 2700 base-pair gene. To test if this indicated a DNA polymerase domain that is relatively noncritical for biological activity, we mutagenized a recombinant plasmid carrying this 5'-terminal region and generated new conditional-lethal mutations that mapped therein. We identified five new ts sites, some having mutated at high frequency (nitrosoguanidine hot spots). New ts mutations were also isolated in phage genes 62 and 44, which map upstream of gene 43 on the T4 chromosome. A preliminary examination of physiological consequences of the ts gene 43 mutations showed that they exhibit effects similar to those of ts lesions that map in other gene 43 segments: some were mutators, some derepressed gene 43 protein synthesis and they varied in the severity of their effects on T4-induced DNA synthesis at nonpermissive temperatures. The availability of the gene 43 clones should make it possible to isolate a variety of lesions that affect different activities of the T4 DNA polymerase and help to define the different domains of this multifunctional protein.
Full Text
The Full Text of this article is available as a PDF (1.9 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen E. F., Albrecht I., Drake J. W. Properties of bacteriophage T4 mutants defective in DNA polymerase. Genetics. 1970 Jun;65(2):187–200. doi: 10.1093/genetics/65.2.187. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CRICK F. H., BARNETT L., BRENNER S., WATTS-TOBIN R. J. General nature of the genetic code for proteins. Nature. 1961 Dec 30;192:1227–1232. doi: 10.1038/1921227a0. [DOI] [PubMed] [Google Scholar]
- EDGAR R. S., LIELAUSIS I. TEMPERATURE-SENSITIVE MUTANTS OF BACTERIOPHAGE T4D: THEIR ISOLATION AND GENETIC CHARACTERIZATION. Genetics. 1964 Apr;49:649–662. doi: 10.1093/genetics/49.4.649. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huang W. M., Lehman I. R. On the exonuclease activity of phage T4 deoxyribonucleic acid polymerase. J Biol Chem. 1972 May 25;247(10):3139–3146. [PubMed] [Google Scholar]
- Huberman J. A., Kornberg A., Alberts B. M. Stimulation of T4 bacteriophage DNA polymerase by the protein product of T4 gene 32. J Mol Biol. 1971 Nov 28;62(1):39–52. doi: 10.1016/0022-2836(71)90129-x. [DOI] [PubMed] [Google Scholar]
- Itakura K., Hirose T., Crea R., Riggs A. D., Heyneker H. L., Bolivar F., Boyer H. W. Expression in Escherichia coli of a chemically synthesized gene for the hormone somatostatin. Science. 1977 Dec 9;198(4321):1056–1063. doi: 10.1126/science.412251. [DOI] [PubMed] [Google Scholar]
- Karam J., McCulley C., Leach M. Genetic control of mRNA decay in T4 phage-infected Escherichia coli. Virology. 1977 Feb;76(2):685–700. doi: 10.1016/0042-6822(77)90251-3. [DOI] [PubMed] [Google Scholar]
- Krisch H. M., Van Houwe G., Belin D., Gibbs W., Epstein R. H. Regulation of the expression of bacteriophage T4 genes 32 and 43. Virology. 1977 May 1;78(1):87–98. doi: 10.1016/0042-6822(77)90080-0. [DOI] [PubMed] [Google Scholar]
- McHenry C. S., Crow W. DNA polymerase III of Escherichia coli. Purification and identification of subunits. J Biol Chem. 1979 Mar 10;254(5):1748–1753. [PubMed] [Google Scholar]
- Müller-Hill B., Kania J. Lac repressor can be fused to beta-galactosidase. Nature. 1974 Jun 7;249(457):561–563. doi: 10.1038/249561a0. [DOI] [PubMed] [Google Scholar]
- Nossal N. G. A T4 bacteriophage mutant which lacks deoxyribonucleic acid polymerase but retains the polymerase-associated nuclease. J Biol Chem. 1969 Jan 10;244(1):218–220. [PubMed] [Google Scholar]
- Nossal N. G., Hershfield M. S. Nuclease activity in a fragment of bacteriophage T4 deoxyribonucleic acid polymerase induced by the amber mutant am B22. J Biol Chem. 1971 Sep 10;246(17):5414–5426. [PubMed] [Google Scholar]
- O'Donnell P. V., Karam J. D. On the direction of reading of bacteriophage T4 gene 43 (deoxyribonucleic acid polymerase). J Virol. 1972 Jun;9(6):990–998. doi: 10.1128/jvi.9.6.990-998.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reha-Krantz L. J., Liesner E. M., Parmaksizoglu S., Stocki S. Isolation of bacteriophage T4 DNA polymerase mutator mutants. J Mol Biol. 1986 May 20;189(2):261–272. doi: 10.1016/0022-2836(86)90508-5. [DOI] [PubMed] [Google Scholar]
- Russel M. Control of bacteriophage T4 DNA polymerase synthesis. J Mol Biol. 1973 Sep 5;79(1):83–94. doi: 10.1016/0022-2836(73)90271-4. [DOI] [PubMed] [Google Scholar]
- Sambrook J. F., Fan D. P., Brenner S. A strong suppressor specific for UGA. Nature. 1967 Apr 29;214(5087):452–453. doi: 10.1038/214452a0. [DOI] [PubMed] [Google Scholar]
- Scheuermann R. H., Echols H. A separate editing exonuclease for DNA replication: the epsilon subunit of Escherichia coli DNA polymerase III holoenzyme. Proc Natl Acad Sci U S A. 1984 Dec;81(24):7747–7751. doi: 10.1073/pnas.81.24.7747. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Venkatesan M., Nossal N. G. Bacteriophage T4 gene 44/62 and gene 45 polymerase accessory proteins stimulate hydrolysis of duplex DNA by T4 DNA polymerase. J Biol Chem. 1982 Oct 25;257(20):12435–12443. [PubMed] [Google Scholar]
- Vieira J., Messing J. The pUC plasmids, an M13mp7-derived system for insertion mutagenesis and sequencing with synthetic universal primers. Gene. 1982 Oct;19(3):259–268. doi: 10.1016/0378-1119(82)90015-4. [DOI] [PubMed] [Google Scholar]
- Warner H. R., Barnes J. E. Deoxyribonucleic acid synthesis in Escherichia coli infected with some deoxyribonucleic acid polymerase-less mutants of bacteriophage T4. Virology. 1966 Jan;28(1):100–107. doi: 10.1016/0042-6822(66)90310-2. [DOI] [PubMed] [Google Scholar]
- Wilson G. G., Murray N. E. Molecular cloning of the DNA ligase gene from bacteriophage T4. I. Characterisation of the recombinants. J Mol Biol. 1979 Aug 15;132(3):471–491. doi: 10.1016/0022-2836(79)90270-5. [DOI] [PubMed] [Google Scholar]