POSSIBLE REGULATION OF DNA METHYLTRANSFERASE EXPRESSION BY RNA PROCESSING IN STREPTOCOCCUS-PNEUMONIAE

Atypical ribosome-binding sites lacking Shine-Dalgarno sequences appea r to be used for translation of the DpnM and DpnA DNA methyltransferas es 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 e ither as a single copy in the chromosome or on a multicopy plasmid.