Related Experiment Videos
The alternate expression of two restriction and modification systems
Molecular & General Genetics : MGG
|January 1, 1983
Summary
Plasmids R124 and R124/3 express restriction-modification (R-M) genes. A regulatory mechanism on translocated F plasmids controls alternative R-M gene expression through DNA rearrangement.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Plasmids R124 and R124/3 possess genes for distinct restriction-modification (R-M) systems.
- Typically, only one set of R-M genes is expressed from these plasmids.
Purpose of the Study:
- To investigate the regulatory mechanism controlling alternative expression of R-M genes from R124 and R124/3 plasmids.
- To understand how gene translocation to F plasmids affects R-M gene expression.
Main Methods:
- Gene translocation of R-M systems to compatible F plasmids.
- Analysis of R-M gene expression in strains carrying both R factors and F plasmids.
- Investigation of DNA sequence rearrangements associated with gene regulation.
Main Results:
- A transacting regulatory mechanism was identified that switches off R-M gene expression on the introduced plasmid.
- The unexpressed genes on the introduced plasmid were subsequently expressed.
- This regulatory control involves physical rearrangement of DNA sequences.
Conclusions:
- The alternative expression of R124 and R124/3 R-M genes is mediated by a transacting regulatory mechanism.
- DNA sequence rearrangement is a key component of this regulatory process.
- This mechanism allows for controlled expression of R-M systems upon plasmid translocation.