NATURE OF ETHYL METHANESULFONATE INDUCED REVERSIONS OF lac$sup -$ MUTANTS OF ESCHERICHIA COLI

Journal Article · Tue Oct 01 04:00:00 EDT 1963 · Genetics (U.S.)

OSTI ID:4629022

Schwartz, N M

Twenty-three ethylmethanesulfonate-induced and nine uv-light-induced lac- mutants wtth greatly reduced levels of BETA -galactosidase activity were isolated in Escherichia coli. EMS mutants were induced to revert to a wild typelike phenotype by aminopurine (AP) but not by uv or EMS. EMS induces transitions, with one class of mutation, probably G: C to A: T being preferentially induced. Ultravioletinduced mutants are induced to revert to a wild type-like phenotype by uv but not be EMS or AP. Ultraviolet therefore appears to induce mostly nontransition type mutations. Feeder revertants of lac- mutants behave like the wild type in transduction tests, in their BETA - galactosidase activity and in the electrophoretic behavior of the revertant enzyme: Nonfeeder revertants are all more or less genetically unstable, produce less BETA -galactosidase and are ailele specific in transduction crosses. They therefore appear to be suppressor-type reversions. The BETA -galactosidases synthesized by nonfeeder'' revertants differ qualitatively from the wild-type enzyme. When a suppressed lac/sup -/ mutant is crossed with a strain bearing the suppressible lac/sup -/ allele, the suppressor mutation is found to map close to the prolac region of the chromosome. One of the suppressors studied was more closely linked to pro and pur than to try, thr, leu, or met. Five different lac/ sup -/ suppressors were jointly transduced with pro, indicating linkage with the pro lac region. (auth)

• Research Organization: Univ. of Chicago
• NSA Number: NSA-17-038789
• OSTI ID: 4629022
• Journal Information: Genetics (U.S.), Journal Name: Genetics (U.S.) Vol. Vol: 48; ISSN GENTA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMINES
BACTERIA
BIOCHEMISTRY
BIOLOGY AND MEDICINE
CHEMICALS
CHROMOSOMES
DRUGS
ELECTROPHORESIS
ENZYMES
ESCHERICHIA COLI
ETHYL RADICALS
GALACTOSIDASE
GENETICS
HETEROCYCLICS
METHANE
MUTAGENS
MUTATIONS
ORGANIC NITROGEN COMPOUNDS
PURINES
RADIATION EFFECTS
STABILITY
SUGARS
SULFONIC ACIDS
TOXICITY
ULTRAVIOLET RADIATION