Pseudoreversion of lactose operator-constitutive mutants
نویسندگان
چکیده
منابع مشابه
Operator-constitutive mutants in the threonine operon of Escherichia coli K-12.
Three Escherichia coli K-12 mutant strains resistant to DL-alpha-amino-beta-hydroxyvaleric acid were isolated in which the expression of the thr operon is constitutive. The localization and dominance properties of the mutations involved, called thrO, are those of operator mutations. The gene sequence is OABC as suggested by earlier studies.
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We isolated 18 independent recessive cold-sensitive cell-division-cycle (cdc) mutants of Saccharomyces cerevisiae, in nine complementation groups. Terminal phenotypes exhibited include medial nuclear division, cytokinesis, and a previously undescribed terminal phenotype consisting of cells with a single small bud and an undivided nucleus. Four of the cold-sensitive mutants proved to be alleles ...
متن کاملLactose carrier mutants of Escherichia coli with changes in sugar recognition (lactose versus melibiose).
The purpose of this research was to identify amino acid residues that mediate substrate recognition in the lactose carrier of Escherichia coli. The lactose carrier transports the alpha-galactoside sugar melibiose as well as the beta-galactoside sugar lactose. Mutants from cells containing the lac genes on an F factor were selected by the ability to grow on succinate in the presence of the toxic...
متن کاملMinimal length of the lactose operator sequence for the specific recognition by the lactose repressor.
A number of specific duplex DNA sequences which correspond to varying lengths of the lactose operator region have been synthesized by a combination of chemical and enzymatic methods. Repressor binding studies on these synthetic duplex operator molecules show that all the nucleotides essential for full lactose operator-repressor interactions are included in a 17-nucleotide-long duplex DNA that c...
متن کامل[Transcription of the lactose operon in Escherichia coli mutants].
Hi protein, a heat-stable low-molecularweight DNA-binding factor previously described by CukierKahn et al. [Proc. Nat. Acad. Sci. USA (1972) 69, 3643-;36471 markedly stimulates in vitro synthesis of lac-specific RNA directed by bacteriophage Xh80 dlac or 480 dlac DNA templates in the presence of purified E. coli RNA polymerase holoenzyme. The extent of stimulation obtained by addition of H1 alo...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1977
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.130.1.100-106.1977