Heterologous gene expression in the hyperthermophilic archaeon Sulfolobus solfataricus

One of the few available systems for gene expression in (hyper)thermophilic Archaea is the virus-based shuttle vector pMJ05 for Sulfolobus solfataricus. Although it is still not fully developed and there are some difficulties arising from the large size of the vector (>20 kb), it has successfully been used for the production of foreign and own proteins in S. solfataricus. Most often, the development of genetic tools for Archaea is held back by the lack of an efficient transformation system. In the case of pMJ05, this difficulty has been alleviated by using the Sulfolobus virus SSV1 as the vector backbone. The ability of the pMJ05 plasmid to spread in the culture as a virus, the availability of an effective selection marker (pyr) and of tunable promoters (araS and tf55α) make this system one of the first choices for heterologous gene expression in (hyper)thermophilic Archaea.