DNA restriction-modification systems in the ethanologen, Zymomonas mobilis ZM4.
To better understand the DNA restriction-modification (R-M) systems for more amenable strain development of the alternative industrial ethanologen, Zymomonas mobilis, three gene knockout mutants were constructed. The gene knockout mutants were tested for their DNA restriction activities by the determination of transformation efficiency using methylated and unmethylated foreign plasmid DNAs. Inactivation of a putative mrr gene encoded by ZMO0028 (zmrr) resulted in a 60-fold increase in the transformation efficiency when unmethylated plasmid DNA was used. This indicated that the putative mrr gene may serve as a type IV restriction-modification system in Z. mobilis ZM4. To assign the function of a putative type I DNA methyltransferase encoded by ZMO1933 (putative S subunit) and ZMO1934 (putative M subunit), the putative S subunit was inactivated. The gene inactivation of ZMO1933 resulted in a 30-fold increase in the transformation efficiency when methylated plasmid DNA was introduced, indicating that the putative S subunit possibly serves as a part of functional type I R-M system(s). Growth studies performed on the mutant strains indicate inactivation of the type I S subunit resulted in a lower maximum specific glucose consumption rate and biomass yield, while inactivation of the type IV Zmrr had the opposite effect, with an increase in the maximum specific growth rate and biomass yield.
The University of New South Wales, Sydney, Australia.
Aidan L
AL
Kerr
Young Jae
YJ
Jeon
Charles J
CJ
Svenson
Peter L
PL
Rogers
Brett A
BA
Neilan
D004262:DNA Restriction Enzymes / Q000235:genetics / Q000378:metabolism; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D055786:Gene Knockout Techniques; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D014169:Transformation, Bacterial; D017355:Zymomonas / Q000201:enzymology* / Q000378:metabolism
D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial; D000431:Ethanol; D008780:Methyltransferases; D004262:DNA Restriction Enzymes