EXPRESSION VECTOR FOR ZYMOMONAS-MOBILIS

This study describes the construction of several useful cloning vectors which can be conjugated from Escherichia coli into Zymomonas mobilis at high frequency, approaching 10-2 per donor or recipient. These vectors contain a broad-host-range replicon and mob site from RSF1010, a chloramphenicol acyltransferase gene under the control of an enteric consensus promoter, and a second mob site (originally derived from RP4). The addition of this second mob site appears to be responsible for a 2-order-of-magnitude increase in the efficiency of transfer into Z. mobilis. Such vectors may be useful for other gram-negative bacteria in which conjugation efficiencies are low. These vectors are stably maintained in Z. mobilis with no detectable loss of plasmid after 50 generations in the absence of selective pressure. One of these, pLOI193, contains the tetracycline gene from pBR322 and associated cloning sites for insertional inactivation. Another, pLOI204, contains a Z. mobilis promoter immediately upstream from a BamHI site which can be used for cloning. This promoter has been shown to efficiently drive the expression of beta-galactosidase in both Z. mobilis and E. coli. This promoter fragment from Z. mobilis has been sequenced, and the site for transcriptional initiation in E. coli and Z. mobilis has been identified.