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Titolo:
The consequences of growth of a mutator strain of Escherichia coli as measured by loss of function among multiple gene targets and loss of fitness
Autore:
Funchain, P; Yeung, A; Stewart, JL; Lin, R; Slupska, MM; Miller, JH;
Indirizzi:
Univ Calif Los Angeles, Dept Microbiol & Mol Genet, Los Angeles, CA 90024 USA Univ Calif Los Angeles Los Angeles CA USA 90024 Los Angeles, CA 90024 USA Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90024 USA Univ Calif Los Angeles Los Angeles CA USA 90024 Los Angeles, CA 90024 USA
Titolo Testata:
GENETICS
fascicolo: 3, volume: 154, anno: 2000,
pagine: 959 - 970
SICI:
0016-6731(200003)154:3<959:TCOGOA>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
SALMONELLA-TYPHIMURIUM; ADAPTIVE EVOLUTION; MULLERS RATCHET; RNA VIRUS; AMPLIFICATION; DNA; RATES; MUTATIONS; ALLELES; REGION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Miller, JH Univ Calif Los Angeles, Dept Microbiol & Mol Genet, 405 HilgardAve, Los Angeles, CA 90024 USA Univ Calif Los Angeles 405 Hilgard Ave Los Angeles CA USA 90024
Citazione:
P. Funchain et al., "The consequences of growth of a mutator strain of Escherichia coli as measured by loss of function among multiple gene targets and loss of fitness", GENETICS, 154(3), 2000, pp. 959-970

Abstract

We have examined the composition of members of mutator populations of Escherichia coli by employing an extensive set of phenotypic screens that allowus to monitor die function of >700 genes, constituting similar to 15% of the genome. We looked at mismatch repair deficient cells after repeated cycles of sing le colony isolation on rich medium to generate lineages that areforced through severe bottlenecks, and compared the results to those for wild-type strains. The mutator lineages continued to accumulate mutations rapidly with each increasing cycle of colony isolation. By die end of the 40th cycle, after similar to 1000 generations, most of the lineages had reduced colony size, 4% had died out, 55% had auxotrophic requirements (increasing to 80% after 60 cycles), and 70% had defects in at least one sugar or catabolic pathway. In addition, 33% had a defect in cell motility, and 26% were either temperature-sensitive or cold-sensitive lethals. On the other hand, only 3% of die wild-type lineages had detectable mutations of any type after 40 cycles. By the 60th cycle, the typical mutator cell carried 4-5 inactive genes among the 15% of the genome being monitored, indicating that theaverage cell carried at least 24-30 inactivated genes distributed throughout the genome. Remarkably, 30% of the lineages had lost title ability to utilize xylose as a carbon source. DNA sequencing revealed that most of the Xyl(-) mutants had a frameshift in a run of eight G's (GGGGGGGG) in the xylBgene, either adding or deleting one -G-. Further analysis indicated that rendering E. coli deficient in mismatch repair unmasks hypermutable sites incertain genes or intergenic regions. Growth curves and competition tests on lineages that passed through 90 cycles of single colony isolation slowed that all lineages suffered reduced fitness. We discuss these results in terms of the value of mutators in cellular evolution.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 14:43:36