Abstract
The roles of bacteriophage T4-encoded thymidylate synthase and dihydrofolate reductase as virion structural components have been further investigated. Two mutants, del(63-32)7 and del(63-32)9, bearing deletions in the gene 63 to 32 region of the T4 genome, were characterized by Southern blotting analysis, as well as by enzyme and immunological assays. Our results have confirmed the original report of Homyk and Weil (Virology 61:505-523, 1974) that del7 and del9 each carries a deletion of about 4.0 kilobases, which totally eliminates the frd gene, encoding dihydrofolate reductase, and the td gene, encoding thymidylate synthase. With the well-characterized deletion mutants, along with newly prepared antisera against T4-encoded thymidylate synthase and dihydrofolate reductase, we have reevaluated the experimental results supporting the idea that T4-induced dihydrofolate reductase and thymidylate synthase are essential T4 baseplate components and antigenic determinants of phage particles. These deletion mutant phages are not targets for neutralization by antisera against either dihydrofolate reductase or thymidylate synthase purified from cloned genes. Furthermore, these newly prepared antisera also cannot neutralize the infectivity of T4D. Those results suggest that the phage-neutralizing components in the old antisera used in the earlier studies were not antibodies against either dihydrofolate reductase or thymidylate synthase but were antibodies against minor components of the purified enzyme preparations. Study of the biological properties of the deletion mutants indicates that T4-induced thymidylate synthase and dihydrofolate reductase play significant roles in growth of the phage beyond their known roles in nucleotide biosynthesis, even though they are apparently not essential for phage viability. The deletion mutants should be useful in defining these roles.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Belfort M., Moelleken A., Maley G. F., Maley F. Purification and properties of T4 phage thymidylate synthetase produced by the cloned gene in an amplification vector. J Biol Chem. 1983 Feb 10;258(3):2045–2051. [PubMed] [Google Scholar]
- Blake M. S., Johnston K. H., Russell-Jones G. J., Gotschlich E. C. A rapid, sensitive method for detection of alkaline phosphatase-conjugated anti-antibody on Western blots. Anal Biochem. 1984 Jan;136(1):175–179. doi: 10.1016/0003-2697(84)90320-8. [DOI] [PubMed] [Google Scholar]
- Capco G. R., Mathews C. K. Bacteriophage-coded thymidylate synthetase. Evidence that the T4 enzyme is a capsid protein. Arch Biochem Biophys. 1973 Oct;158(2):736–743. doi: 10.1016/0003-9861(73)90568-7. [DOI] [PubMed] [Google Scholar]
- Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
- Homyk T., Jr, Weil J. Deletion analysis of two nonessential regions of the T4 genome. Virology. 1974 Oct;61(2):505–523. doi: 10.1016/0042-6822(74)90286-4. [DOI] [PubMed] [Google Scholar]
- Kozloff L. M. Composition of the T4D bacteriophage baseplate and the binding of the central tail plug. Prog Clin Biol Res. 1981;64:327–342. [PubMed] [Google Scholar]
- Kozloff L. M., Crosby L. K., Lute M. Bacteriophage T4 baseplate components. III. Location and properties of the bacteriophage structural thymidylate synthetase. J Virol. 1975 Dec;16(6):1409–1419. doi: 10.1128/jvi.16.6.1409-1419.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kozloff L. M., Crosby L. K., Lute M., Hall D. H. Bacteriophage T4 baseplate components. II. Binding and location of bacteriophage-induced dihydrofolate reductase. J Virol. 1975 Dec;16(6):1401–1408. doi: 10.1128/jvi.16.6.1401-1408.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kozloff L. M., Lute M., Crosby L. K. Bacteriophage T4 virion baseplate thymidylate synthetase and dihydrofolate reductase. J Virol. 1977 Sep;23(3):637–644. doi: 10.1128/jvi.23.3.637-644.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kozloff L. M., Verses C., Lute M., Crosby L. K. Bacteriophage tail components. II. Dihydrofolate reductase in T4D bacteriophage. J Virol. 1970 Jun;5(6):740–753. doi: 10.1128/jvi.5.6.740-753.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MATHEWS C. K., SUTHERLAND K. E. COMPARATIVE BIOCHEMISTRY OF BACTERIAL AND PHAGE-INDUCED DIHYDROFOLATE REDUCTASES. J Biol Chem. 1965 May;240:2142–2147. [PubMed] [Google Scholar]
- Mathews C. K., Crosby L. K., Kozloff L. M. Inactivation of T4D bacteriophage by antiserum against bacteriophage dihydrofolate reductase. J Virol. 1973 Jul;12(1):74–78. doi: 10.1128/jvi.12.1.74-78.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mathews C. K. Growth of a dihydrofolate reductaseless mutant of bacteriophage T4. J Virol. 1967 Oct;1(5):963–967. doi: 10.1128/jvi.1.5.963-967.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mathews C. K. Identity of genes coding for soluble and structural dihydrofolate reductases in bacteriophage T4. J Virol. 1971 Apr;7(4):531–533. doi: 10.1128/jvi.7.4.531-533.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mathews C. K. Phage Growth and Deoxyribonucleic Acid Synthesis in Escherichia coli Infected by a Thymine-Requiring Bacteriophage. J Bacteriol. 1965 Sep;90(3):648–652. doi: 10.1128/jb.90.3.648-652.1965. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matthews C. K. Deoxyribonucleic acid metabolism and virus-induced enzyme synthesis in a thymine-requiring bacterium infected by a thymine-requiring bacteriophage. Biochemistry. 1966 Jun;5(6):2092–2100. doi: 10.1021/bi00870a042. [DOI] [PubMed] [Google Scholar]
- Mosher R. A., DiRenzo A. B., Mathews C. K. Bacteriophage T4 virion dihydrofolate reductase: approaches to quantitation and assessment of function. J Virol. 1977 Sep;23(3):645–658. doi: 10.1128/jvi.23.3.645-658.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mosher R. A., Mathews C. K. Bacteriophage T4-coded dihydrofolate reductase: synthesis, turnover, and location of the virion protein. J Virol. 1979 Jul;31(1):94–103. doi: 10.1128/jvi.31.1.94-103.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nakamura K., Kozloff L. M. Folate polyglutamates in T4D bacteriophage and T4D-infected Escherichia coli. Biochim Biophys Acta. 1978 May 3;540(2):313–319. doi: 10.1016/0304-4165(78)90144-7. [DOI] [PubMed] [Google Scholar]
- Purohit S., Bestwick R. K., Lasser G. W., Rogers C. M., Mathews C. K. T4 phage-coded dihydrofolate reductase. Subunit composition and cloning of its structural gene. J Biol Chem. 1981 Sep 10;256(17):9121–9125. [PubMed] [Google Scholar]
- Purohit S., Mathews C. K. Nucleotide sequence reveals overlap between T4 phage genes encoding dihydrofolate reductase and thymidylate synthase. J Biol Chem. 1984 May 25;259(10):6261–6266. [PubMed] [Google Scholar]
- Watts N. R., Coombs D. H. Analysis of near-neighbor contacts in bacteriophage T4 wedges and hubless baseplates by using a cleavable chemical cross-linker. J Virol. 1989 Jun;63(6):2427–2436. doi: 10.1128/jvi.63.6.2427-2436.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]