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Myxococcus xanthus msDNA.Mx162 exists as a complex with proteins
M Viswanathan1, M Inouye, S Inouye
1Department of Biochemistry, Robert Wood Johnson Medical School at Rutgers, University of Medicine and Dentistry of New Jersey, Piscataway 08854.
The Journal of Biological Chemistry
|August 15, 1989
Summary
Specific proteins bind to myxobacterial branched DNA (msDNA) in Myxococcus xanthus. These protein-msDNA complexes are crucial for msDNA function and cellular localization.
Area of Science:
- Molecular Biology
- Microbiology
- Genetics
Background:
- Myxococcus xanthus possesses a unique branched RNA-linked DNA (msDNA).
- Reverse transcriptase is essential for msDNA synthesis.
- The specific function and cellular interactions of msDNA remain incompletely understood.
Purpose of the Study:
- To investigate the interaction of proteins with msDNA.Mx162 in Myxococcus xanthus.
- To characterize the nature of msDNA-protein complexes within the cell.
Main Methods:
- Gel retardation assays were employed to detect protein binding to msDNA.Mx162.
- Proteinase K treatment was used to confirm protein involvement.
- In vivo footprinting with dimethyl sulfate identified protected DNA regions.
- Glycerol gradient centrifugation analyzed the sedimentation properties of msDNA-protein complexes.
Main Results:
- Gel retardation assays revealed two distinct protein-binding sites on msDNA.Mx162.
- Binding was specific to msDNA, as indicated by competition assays.
- In vivo footprinting showed protection of a specific deoxynucleotide stretch (60-161).
- msDNA.Mx162 was found to exist in two distinct complexes (14 S and 5 S) in cell lysates.
Conclusions:
- Specific proteins associate with msDNA.Mx162 in Myxococcus xanthus.
- These protein-msDNA interactions protect specific DNA regions.
- msDNA.Mx162 forms distinct complexes with proteins, suggesting a role in cellular organization or function.