Abstract
Some preparations of beta-galactosidase from strains of Escherichia coli carrying point mutations in their lacZ genes did not precipitate with antibody as effectively as wild-type enzyme, but did not appear to be chain-terminating mutations as judged by polarity measurements and suppression. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of crude extracts of induced Lac+ strains revealed that the monomer of beta-galactosidase ran as a band uncontaminated by other cellular proteins. This method was used to identify missense mutations in the alpha and beta portions of the lacZ gene. Six of 13 mutations investigated were judged to be missense by this criterion. Measurement of the degree of polarity, the ability to complement a nonsense mutation at the operator-distal extremity of the gene (omega-complementation), and suppressibility by 12 nonsense suppressors allowed the assignment of six other mutations as either number or ochre. The protein figments produced by these six nonsense mutations appeared to be degraded in vivo. One mutation that could not be classified was either a missense mutation whose protein product was degraded or a very leak nonsense mutation. Two lacZ alleles were suppressed by the ochre suppressors supM and supN, although they were missense by other criteria. The ability of supM to suppress both nonsense and missense mutations can be explained if it is derived from a tyrosine transfer ribonucleic acid with a modified base in the first position of the anticodon. The mutations assigned to the missense class were not suppressed by the missense suppressors supH, supQ, glyV, glyU, or glyT. Our results suggest that the criteria used in the past to distinguish between nonsense and missense mutations may not be conclusive even when used together.
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- ADELBERG E. A., BURNS S. N. Genetic variation in the sex factor of Escherichia coli. J Bacteriol. 1960 Mar;79:321–330. doi: 10.1128/jb.79.3.321-330.1960. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bukhari A. I., Zipser D. Mutants of Escherichia coli with a defect in the degradation of nonsense fragments. Nat New Biol. 1973 Jun 20;243(129):238–241. doi: 10.1038/newbio243238a0. [DOI] [PubMed] [Google Scholar]
- Crick F. H. Codon--anticodon pairing: the wobble hypothesis. J Mol Biol. 1966 Aug;19(2):548–555. doi: 10.1016/s0022-2836(66)80022-0. [DOI] [PubMed] [Google Scholar]
- Eggertsson G., Adelberg E. A. Map positions and specificities of suppressor mutations in Escherichia coli K-12. Genetics. 1965 Aug;52(2):319–340. doi: 10.1093/genetics/52.2.319. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Eggertsson G. Suppressors causing temperature sensitivity of growth in Escherichia coli. Genetics. 1968 Oct;60(2):269–280. doi: 10.1093/genetics/60.2.269. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fowler A. V., Zabin I. Beta-galactosidase: immunological studies of nonsense, missense and deletion mutants. J Mol Biol. 1968 Apr 14;33(1):35–47. doi: 10.1016/0022-2836(68)90279-9. [DOI] [PubMed] [Google Scholar]
- Goldberg A. L. Degradation of abnormal proteins in Escherichia coli (protein breakdown-protein structure-mistranslation-amino acid analogs-puromycin). Proc Natl Acad Sci U S A. 1972 Feb;69(2):422–426. doi: 10.1073/pnas.69.2.422. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldschmidt R. In vivo degradation of nonsense fragments in E. coli. Nature. 1970 Dec 19;228(5277):1151–1154. doi: 10.1038/2281151a0. [DOI] [PubMed] [Google Scholar]
- Gorini L. Informational suppression. Annu Rev Genet. 1970;4:107–134. doi: 10.1146/annurev.ge.04.120170.000543. [DOI] [PubMed] [Google Scholar]
- Greeb J., Atkins J. F., Loper J. C. Histidinol dehydrogenase (his D) mutants of Salmonella typhimurium. J Bacteriol. 1971 May;106(2):421–431. doi: 10.1128/jb.106.2.421-431.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hartman P. E., Hartman Z., Stahl R. C. Classification and mapping of spontaneous and induced mutations in the histidine operon of Salmonella. Adv Genet. 1971;16:1–34. doi: 10.1016/s0065-2660(08)60352-1. [DOI] [PubMed] [Google Scholar]
- JACOB F., ULLMAN A., MONOD J. LE PROMOTEUR, 'EL'EMENT G'EN'ETIQUE N'ECESSAIRE 'A L'EXPRESSION D'UN OP'ERON. C R Hebd Seances Acad Sci. 1964 Mar 16;258:3125–3128. [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- LURIA S. E., BURROUS J. W. Hybridization between Escherichia coli and Shigella. J Bacteriol. 1957 Oct;74(4):461–476. doi: 10.1128/jb.74.4.461-476.1957. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langridge J., Campbell J. H. Classification and intragenic position of mutations in the beta-galactosidase gene of Escherichia coli. Mol Gen Genet. 1969;103(4):339–347. doi: 10.1007/BF00383484. [DOI] [PubMed] [Google Scholar]
- Langridge J. Genetic and enzymatic experiments relating to the quaternary structure of beta-galactosidase. Aust J Biol Sci. 1974 Jun;27(3):321–330. doi: 10.1071/bi9740321. [DOI] [PubMed] [Google Scholar]
- Langridge J. Genetic evidence for the disposition of the substrate binding site of beta-galactosidase. Proc Natl Acad Sci U S A. 1968 Aug;60(4):1260–1267. doi: 10.1073/pnas.60.4.1260. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langridge J. Mutation spectra and the neutrality of mutations. Aust J Biol Sci. 1974 Jun;27(3):309–319. doi: 10.1071/bi9740309. [DOI] [PubMed] [Google Scholar]
- Margolies M. N., Goldberger R. F. Correlation between mutation type and the production of cross-reacting material in mutants of the A gene of the histidine operon in Salmonella typhimurium. J Bacteriol. 1968 Feb;95(2):507–519. doi: 10.1128/jb.95.2.507-519.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morrison S. L., Zipser D. Polypeptide products of nonsense mutations. I. Termination fragments from nonsense mutations in the Z gene of the lac operon of Escherichia coli. J Mol Biol. 1970 Jun 14;50(2):359–371. doi: 10.1016/0022-2836(70)90198-1. [DOI] [PubMed] [Google Scholar]
- Murgola E. J., Yanofsky C. Selection for new amino acids at position 211 of the tryptophan synthetase alpha chain of Escherichia coli. J Mol Biol. 1974 Jul 15;86(4):775–784. doi: 10.1016/0022-2836(74)90353-2. [DOI] [PubMed] [Google Scholar]
- Nishimura S. Minor components in transfer RNA: their characterization, location, and function. Prog Nucleic Acid Res Mol Biol. 1972;12:49–85. [PubMed] [Google Scholar]
- Orias E., Gartner T. K., Lannan J. E., Betlach M. Close linkage between ochre and missense suppressors in Escherichia coli. J Bacteriol. 1972 Mar;109(3):1125–1133. doi: 10.1128/jb.109.3.1125-1133.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PERRIN D. Immunological studies with genetically altered beta-galactosidases. Ann N Y Acad Sci. 1963 May 8;103:1058–1066. doi: 10.1111/j.1749-6632.1963.tb53757.x. [DOI] [PubMed] [Google Scholar]
- Reid M. S., Bieleski R. L. A simple apparatus for vertical flat-sheet polyacrylamide gel electrophoresis. Anal Biochem. 1968 Mar;22(3):374–381. doi: 10.1016/0003-2697(68)90278-9. [DOI] [PubMed] [Google Scholar]
- Russell R. R., Pittard A. J. New suppresor in Escherichia coli. J Bacteriol. 1971 Sep;107(3):736–740. doi: 10.1128/jb.107.3.736-740.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith R. E., Zweerink H. J., Joklik W. K. Polypeptide components of virions, top component and cores of reovirus type 3. Virology. 1969 Dec;39(4):791–810. doi: 10.1016/0042-6822(69)90017-8. [DOI] [PubMed] [Google Scholar]
- Soll L. Mutational alterations of tryptophan-specific transfer RNA that generate translation suppressors of the UAA, UAG and UGA nonsense codons. J Mol Biol. 1974 Jun 25;86(2):233–243. doi: 10.1016/0022-2836(74)90015-1. [DOI] [PubMed] [Google Scholar]
- Squires C., Carbon J. Normal and mutant glycine transfer RNAs. Nat New Biol. 1971 Oct 27;233(43):274–277. doi: 10.1038/newbio233274a0. [DOI] [PubMed] [Google Scholar]
- Squires C., Konrad B., Kirschbaum J., Carbon J. Three adjacent transfer RNA genes in Escherichia coli. Proc Natl Acad Sci U S A. 1973 Feb;70(2):438–441. doi: 10.1073/pnas.70.2.438. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taylor A. L., Trotter C. D. Linkage map of Escherichia coli strain K-12. Bacteriol Rev. 1972 Dec;36(4):504–524. doi: 10.1128/br.36.4.504-524.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weber K., Kuter D. J. Reversible denaturation of enzymes by sodium dodecyl sulfate. J Biol Chem. 1971 Jul 25;246(14):4504–4509. [PubMed] [Google Scholar]
- Weber K., Osborn M. The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J Biol Chem. 1969 Aug 25;244(16):4406–4412. [PubMed] [Google Scholar]
- Whitfield H. J., Jr, Martin R. G., Ames B. N. Classification of aminotransferase (C gene) mutants in the histidine operon. J Mol Biol. 1966 Nov 14;21(2):335–355. doi: 10.1016/0022-2836(66)90103-3. [DOI] [PubMed] [Google Scholar]
- Yaniv M., Folk W. R., Berg P., Soll L. A single mutational modification of a tryptophan-specific transfer RNA permits aminoacylation by glutamine and translation of the codon UAG. J Mol Biol. 1974 Jun 25;86(2):245–260. doi: 10.1016/0022-2836(74)90016-3. [DOI] [PubMed] [Google Scholar]
- Yanofsky C. Gene structure and protein structure. Harvey Lect. 1967;61:145–168. [PubMed] [Google Scholar]
