Isolation and characterization of a temperature-sensitive amber suppressor mutant of Escherichia coli K12

1973 ◽  
Vol 123 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Toshio Nagata ◽  
Takashi Horiuchi
Keyword(s):  
Escherichia Coli ◽  
Temperature Sensitive ◽  
Escherichia Coli K12 ◽  
Isolation And Characterization ◽  
Amber Suppressor

scholarly journals ISOLATION AND CHARACTERIZATION OF dnaX AND dnaY TEMPERATURE-SENSITIVE MUTANTS OF ESCHERICHIA COLI

Genetics ◽  
1979 ◽  
Vol 92 (4) ◽  
pp. 1041-1059
Author(s):  
Joan M Henson ◽  
Herman Chu ◽  
Carleen A Irwin ◽  
James R Walker
Keyword(s):  
Escherichia Coli ◽  
Dna Synthesis ◽  
Fold Increase ◽  
Temperature Sensitive ◽  
E Coli ◽  
Temperature Sensitive Mutants ◽  
Isolation And Characterization ◽  
Ts Mutations

ABSTRACT Escherichia coli mutants with temperature-sensitive (ts) mutations in dnaX and dnaY genes have been isolated. Based on transduction by phage PI, dnaX and Y have been mapped at minutes 10.4-10.5 and 12.1, respectively, in the sequence dnaX purE dnaY. Both dnaXts36 and YtslO are recessive to wild-type alleles present on episomes. F13 carries both dnaX  + and Y  +; the shorter F210 carries dnaY  +, but not X  +. Lambda transducing phages that carry dnaX  + or Y  + have been isolated, and hybrid plasmids of Col E1 and E. coli DNA from the CLARKE and CARBON (1976) collection also carry portions of the dnaX purE dnaY region. Results obtained with the λ transducing phages and the hybrid plasmids suggest that dnaX is a different gene from the previously characterized dnaZ gene, which is also near minute 10.5.—The dnaXts36 mutant, after a shift to 42°, stopped DNA synthesis gradually, and the total amount of DNA increased two-fold. When this mutant was shifted to M°, the rate of DNA synthesis dropped immediately and the final increment of DNA was only 10% of the initial amount. Replicative DNA synthesis in toluene-treated cells was completely inhibited at 42° and was partially in-hibited even at 30°.—When the dnaYtslO mutant was shifted to 42°, DNA synthesis gradually stopped, and the amount of DNA increased 3.6-fold. At 44°, residual DNA synthesis amounted to a two-fold increase. Replicative DNA synthesis in vitro in toluene-treated cells was inactivated after 20 minutes at 42° or by "preincubation" of cells at 42° before toluene treatment.— The dnaX and dnaY products probably function in polymerization of DNA, although participation also in initiation cannot be excluded.

Isolation and characterization of cAMP suppressor mutants of Escherichia coli K12

1981 ◽  
Vol 182 (3) ◽  
pp. 480-489 ◽  
Author(s):  
Thoyd Melton ◽  
Linda L. Snow ◽  
Cynthia S. Freitag ◽  
Walter J. Dobrogosz
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli K12 ◽  
Isolation And Characterization ◽  
Suppressor Mutants

Isolation and characterization of visible light-sensitive mutants of Escherichia coli K12

1991 ◽  
Vol 219 (3) ◽  
pp. 393-398 ◽  
Author(s):  
Kazumasa Miyamoto ◽  
Kenji Nakahigashi ◽  
Koichi Nishimura ◽  
Hachiro Inokuchi
Keyword(s):  
Escherichia Coli ◽  
Visible Light ◽  
Escherichia Coli K12 ◽  
Isolation And Characterization
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