The invention provides origin of replication sequences and replication genes and proteins for a plasmid functional in Fusobacterium (e.g., F. nucleatum) and related species. Provided by the invention are also plasmids and vectors that can replicate in Fusobacterium. Further, the invention provides shuttle vectors that can replicate in Fusobacterium and in other microorganisms, such as E. coli. Still further, the present invention provides host cells comprising the plasmids and shuttle vectors, and methods for transformation of the host cells with the plasmid and shuttle vectors of the invention.