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Possible regulation of DNA methyltransferase expression by RNA processing in Streptococcus pneumoniae
S A Lacks1, B Greenberg, A G Sabelnikov
1Brookhaven National Laboratory, Upton, NY 11973, USA.
Abstract:
Atypical ribosome-binding sites lacking Shine-Dalgarno sequences appear to be used for translation of the DpnM and DpnA DNA methyltransferases of the DpnII restriction system. Preliminary results indicate that the 5'-endpoints of DpnII system mRNAs result from degradation of the original transcript. These tentative findings serve as the basis for a possible regulatory model that would accommodate the DpnII cassette either as a single copy in the chromosome or on a multicopy plasmid.
Insights
The DpnII restriction system uses unusual ribosome-binding sites for DNA methyltransferase translation. mRNA degradation may regulate this system, whether on a chromosome or plasmid.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- The DpnII restriction system is a DNA modification system.
- Understanding its gene expression regulation is crucial.
Purpose of the Study:
- To investigate the translation initiation mechanism of DpnM and DpnA in the DpnII system.
- To explore the potential role of mRNA degradation in regulating DpnII gene expression.
Main Methods:
- Analysis of DpnII system mRNAs.
- Identification of ribosome-binding sites.
- Investigating transcript 5'-endpoints.
Main Results:
- Atypical ribosome-binding sites, lacking Shine-Dalgarno sequences, are utilized for DpnM and DpnA translation.
- Preliminary data suggest that mRNA 5'-endpoints originate from transcript degradation.
Conclusions:
- The DpnII system may employ a novel translational control mechanism.
- mRNA degradation could be a regulatory factor for the DpnII cassette, adaptable to chromosomal or plasmid contexts.