DNA supercoiling: A regulatory signal for the repressor
نویسندگان
چکیده
منابع مشابه
DNA supercoiling inhibits DNA knotting
Despite the fact that in living cells DNA molecules are long and highly crowded, they are rarely knotted. DNA knotting interferes with the normal functioning of the DNA and, therefore, molecular mechanisms evolved that maintain the knotting and catenation level below that which would be achieved if the DNA segments could pass randomly through each other. Biochemical experiments with torsionally...
متن کاملDNA knots and DNA supercoiling.
Type II DNA topoisomerases permit passages of double stranded DNA segments through each other and this is achieved via a complex mechanism involving a transient cleavage of one duplex, a passage of the second duplex through the topoisomerase-spanned cleavage site and finally resealing of the cut duplex. Type II DNA topoisomerases facilitate many DNA transactions requiring manipulation of long D...
متن کاملDNA supercoiling, a critical signal regulating the basal expression of the lac operon in Escherichia coli
Escherichia coli lac repressor (LacI) is a paradigmatic transcriptional factor that controls the expression of lacZYA in the lac operon. This tetrameric protein specifically binds to the O1, O2 and O3 operators of the lac operon and forms a DNA loop to repress transcription from the adjacent lac promoter. In this article, we demonstrate that upon binding to the O1 and O2 operators at their nati...
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Gene expression regulation is a fundamental biological process which deploys specific sets of genomic information depending on physiological or environmental conditions. Several transcription factors (including lac repressor, LacI) are present in the cell at very low copy number and increase their local concentration by binding to multiple sites on DNA and looping the intervening sequence. In t...
متن کاملSupercoiling and denaturation in Gal repressor/heat unstable nucleoid protein (HU)-mediated DNA looping.
The overall topology of DNA profoundly influences the regulation of transcription and is determined by DNA flexibility as well as the binding of proteins that induce DNA torsion, distortion, and/or looping. Gal repressor (GalR) is thought to repress transcription from the two promoters of the gal operon of Escherichia coli by forming a DNA loop of approximately 40 nm of DNA that encompasses the...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2014
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.1320644111