Summary
Strains of Salmonella typhimurium that contain the aroC321 allele require phenylalanine, tyrosine, and tryptophan for growth but revert to tryptophan-prototrophy at high frequencies (about 10-4 per cell plated). The Trp+ derivatives remain auxotrophic for phenylalanine and tyrosine and are genetically unstable, in that they readily give rise to cells that require all three aromatic amino acids. On the basis of growth characteristics and genetic instability, it has been proposed that reversion to tryptophan-prototrophy in aroC321 strains occurs by genetic duplication. This paper provides genetic evidence in support of that hypothesis. The data indicate, moreover, that the tryptophan prototrophs contain a duplication that extends at least from glpT to xyl, a region of greater than 30% of the Salmonella chromosome. The aroC locus is found within the duplicated region, and aroC321/aroC321 merodiploids apparently grow as tryptophan prototrophs because of a genedosage effect.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Anderson P, Roth J (1981) Spontaneous tandem genetic duplications in Salmonella typhimurium arise by unequal recombination between rRNA (rrn) cistrons. Proc Natl Acad Sci USA 78:3113–3117
Anderson RP, Miller CG, Roth JR (1976) Tandem duplications of the histidine operon observed following generalized transduction in Salmonella typhimurium. J Mol Biol 105:201–218
Anderson RP, Roth JR (1977) Tandem genetic duplications in phage and bacteria. Annu Rev Microbiol 31:473–505
Atkins JF (1969) Further analysis of an unstable aromatic auxotroph of Salmonella typhimurium. PhD Thesis, Dublin University, Ireland
Blake PJ (1965) Genetic analysis of unstable aromatic auxotrophs of Salmonella typhimurium. PhD Thesis, Dublin University, Ireland
Ellwood M, Nomura M (1982) Chromosomal locations of the genes for rRNA in Escherichia coli K-12. J Bacteriol 149:458–468
Folk WR, Berg P (1971) Duplication of the structural gene for glycyl-transfer RNA synthetase in Escherichia coli. J Mol Biol 58:595–610
Gollub E, Zalkin H, Sprinson DB (1967) Correlation of genes and enzymes, and studies on regulation of the aromatic pathway in Salmonella. J Biol Chem 242:5323–5328
Gutnick D, Calvo JM, Klopotowski T, Ames BN, (1969) Compounds which serve as the sole source of carbon or nitrogen for Salmonella typhimurium LT-2. J Bactriol 100:215–219
Hill CW, Combriato G (1973) Genetic duplications induced at very high frequency by ultraviolet irradiation in Escherichia coli. Mol Gen Genet 127:197–214
Hill CW, Grafstrom RH, Harnish BW, Hillman BS (1977) Tandem duplications resulting from recombination between ribosomal RNA genes in Escherichia coli. J Mol Biol 116:407–428
Hill CW, Harnish BW (1982) Transposition of a chromosomal segment bounded by redundant rRNA genes into other rRNA genes in Escherichia coli. J Bacteriol 149:449–457
Hill CW, Harnish BW (1981) Inversions between ribosomal RNA genes of Escherichia coli. Proc Natl Acad Sci USA 78:7069–7072
Hoffmann GR, Morgan RW (1976) The effect of ultraviolet light on the frequency of a genetic duplication in Salmonella typhimurium. Radiat Res 67:114–119
Hoffmann GR, Morgan RW, Harvey RC (1978a) Effects of chemical and physical mutagens on the frequency of a large genetic duplication in Salmonella typhimurium, I. Induction of duplications. Mutat Res 52:73–80
Hoffmann GR, Morgan RW, Kirven R (1978b) Effects of chemical and physical mutagens on the frequency of a large genetic duplication in Salmonella typhimurium, II. Stimulation of duplication-loss from merodiploids. Mutat Res 52:81–86
Ledbetter MLS, Hotchkiss RD (1975) Recombination as a requirement for segregation of a partially diploid mutant of pneumococcus. Genetics 80:679–694
Lehner AF, Hill CW (1980) Involvement of ribosomal ribonucleic acid operons in Salmonella typhimurium chromosomal rearrangements. J Bacteriol 143:492–498
Murray GE, Smith-Keary PF (1976) A recombination-dependent replicating instability in Salmonella typhimurium. Mutat Res 36:283–290
Sanderson KE (1972) Linkage map of Salmonella typhimurium, Edition IV. Bacteriol Rev 36:558–586
Sanderson KE, Hartman PE (1978) Linkage map of Salmonella typhimurium, Edition V. Microbiol Rev 42:471–519
Schmieger H (1972) Phage P22-mutants with increased or decreased transduction abilities. Mol Gen Genet 119:75–88
Simonian MH, Mosteller RD (1976) Increased loss of duplicated genes in streptomycin-resistant (strA) mutants of E. coli K12. J Bacteriol 126:382–384
Smith HO, Levine M (1967) A phage P22 gene controlling integration of prophage. Virology 31:207–216
Straus DS (1974) Induction by mutagens of tandem gene duplications in the glyS region of the Escherichia coli chromosome. Genetics 78:823–830
Straus DS, Hoffmann GR (1975) Selection for a large genetic duplication in Salmonella typhimurium. Genetics 80:227–237
Straus DS, Straus L D'A (1976) Large overlapping tandem genetic duplications in Salmonella typhimurium. J Mol Biol 103:143–153
Vogel HJ, Bonner DM (1956) Acetylornithinase of E. coli: A partial purification and some properties. J Biol Chem 218:97–106
Winfield SL, Falkinham JO III (1981) Effect of rec A and polA mutations on gene duplication in Salmonella typhimurium. Mutat Res 91:15–20
Author information
Authors and Affiliations
Additional information
Communicated by H. Böhme
Rights and permissions
About this article
Cite this article
Hoffmann, G.R., Walkowicz, M.J., Mason, J.M. et al. Genetic instability associated with the aroC321 allele in Salmonella typhimurium involves genetic duplication. Mol Gen Genet 190, 183–188 (1983). https://doi.org/10.1007/BF00330638
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00330638