A mutant of Escherichia coli with a new, highly efficient promoter for the lactose operon.
نویسندگان
چکیده
We have isolated a mutant of E. coli whose maximal rate of synthesis of lac mRNA is 25-fold greater than that of its parental wild-type strain. The mutant also shows alterations in the kinetics of beta-galactosidase synthesis, the functional half-life of beta-galactosidase mRNA, and the properties of lac repressor.
منابع مشابه
CONSTRUCTION OF RECOMBINANT PLASMIDS FOR PERIPLASMIC EXPRESSION OF HUMAN GROWTH HORMONE IN ESCHERICHIA COLI UNDER T7 AND LAC PROMOTERS
In order to study the periplasmic expression of human growth hormone (hGH) in Escherichia coli, the related cDNA was inserted in two expression plasmids carrying pelB signal peptide, one with lac bacterial promoter and the other with a bacteriophage T7-based promoter. The recombinant plasmids were moved to TG1 and BL21 strains of E. coli, respectively. To induce the expression systems, IPTG and...
متن کاملLactose operon transcription from wild-type and L8-UV5 lac promoters in Escherichia coli treated with chloramphenicol.
In cells treated with chloramphenicol and the inducer isopropyl-beta-D-thiogalacto-pyranoside, messenger ribonucleic acid transcription from the wild-type lac promoter was not detected. Transcription occurred from the mutant UV5-L8 promoter. The transcripts were of variable length; some included the whole Z gene. No major site of transcription arrest within the Z gene was apparent.
متن کاملCyclic adenosine monophosphate-independent mutants of the lactose operon of Escherichia coli.
In Escherichia coli the transcription of the lactose operon, like other catabolite-sensitive operons, requires catabolite gene activator protein and 3',5'-cyclic adenosine monophosphate in addition to ribonucleic acid polymerase. We isolated and analyzed lac(+) revertants from a crp(-) strain of E. coli. We found that revertants with a higher level of expression only for the lac operon lie in t...
متن کاملRNA polymerase supply and flux through the lac operon in Escherichia coli
Chromatin immunoprecipitation, followed by quantification of immunoprecipitated DNA, can be used to measure RNA polymerase binding to any DNA segment in Escherichia coli By calibrating measurements against the signal from a single RNA polymerase bound at a single promoter, we can calculate both promoter occupancy levels and the flux of transcribing RNA polymerase through transcription units. He...
متن کاملElements involved in catabolite repression and substrate induction of the lactose operon in Lactobacillus casei.
In Lactobacillus casei ATCC 393, the chromosomally encoded lactose operon, lacTEGF, encodes an antiterminator protein (LacT), lactose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) elements (LacE and LacF), and a phospho-beta-galactosidase. lacT, lacE, and lacF mutant strains were constructed by double crossover. The lacT strain displayed constitutive termination at a ri...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 70 12 شماره
صفحات -
تاریخ انتشار 1973