An autonomously replicating transforming vector for Sulfolobus solfataricus

A plasmid able to transform and to be stably maintained both inSulfolobus solfataricus and in Escherichia coliwas constructed by insertion into an E. coli plasmid of the autonomously replicating sequence of the virus particle SSV1 and a suitable mutant of the hph (hygromycin phosphotransferase) gene as the transformation marker. The vector suffered no rearrangement and/or chromosome integration, and its copy number inSulfolobus was increased by exposure of the cells to mitomycin C.