Recombinase-mediated cassette exchange (RMCE) system for functional genomics studies in Mycoplasma mycoides.

Background: We have previously established technologies enabling us to engineer the Mycoplasma mycoides genome while cloned in the yeast Saccharomyces cerevisiae, followed by genome transplantation into Mycoplasma capricolum recipient cells to produce M. mycoides with an altered genome. To expand the toolbox for genomic modifications, we designed a strategy based on the Cre/loxP-based Recombinase-Mediated Cassette Exchange (RMCE) system for functional genomics analyses.

Results: In this paper, we demonstrated replacement of an approximately 100 kb DNA segment of the M. mycoides genome with a synthetic DNA counterpart in two orientations. The function of the altered genomes was then validated by genome transplantation and phenotypic characterization of the transplanted cells.

Conclusion: This method offers an easy and efficient way to manipulate the M. mycoides genome and will be a valuable tool for functional genomic studies, such as genome organization and minimization.