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‘Muprints’ of the lac operon demonstrate physiological control over the randomness of in vivo transposition
Author(s) -
Wang Xiuhua,
Higgins N. Patrick
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb01054.x
Subject(s) - operon , biology , lac operon , lac repressor , transposition (logic) , bacteriophage mu , genetics , l arabinose operon , transposable element , trp operon , repressor , gene , gal operon , plasmid , escherichia coli , genome , gene expression , linguistics , philosophy
Summary A method called Muprinting has been developed that uses PCR to generate a detailed picture of the bacteriophage Mu transposition sites in chosen domains of the bacterial chromosome. Muprinting experiments In Escherichia coli show that the frequency of phage integration changes dramatically near two repressor binding sites in the lac operon. When the lac operon was repressed, hotspots for Mu transposition were found near the O 1 and O 2 operators that are proposed to make a repression loop. When cells were grown in lactose, Mu transposition near these operators was greatly diminished. Striking changes In transposition frequencies were limited to the control region and were not found in a region of the lacZ gene lying beyond the O 2 operator. Muprints of the bgl operon showed a different pattern; hotspots for Mu transposition detected in sequences upstream of the bglC promoter when the operon was silenced changed when the operon became activated by mutation. By targeting transposition to the regulatory regions around non‐expressed genes, Mu may demonstrate a self‐restraint mechanism that allows the virus to move through its host genome without disrupting the functions that contribute to a healthy cell physiology.