A Brevibacterium lactofermentum 16S rRNA gene used as target site for homologous recombination

Genes for rRNA are highly conserved and present in multiple copies in most prokaryotic organisms increasing the number of theoretical sites for homolo gous recombination. They might be targets for integration events between un related microorganisms providing that an efficient genetic transfer is pres ent. We have used a plasmid containing a portion of the 16S rRNA gene from the rrnD operon of Brevibacterium lactofermentum to transform the same stra in resulting in non-essential inactivation of various rrn operons. Integrat ion of the transforming DNA occurs in all cases. The system may be used to test possible gene transfer at least among closely related strains and is o f great interest for integration of foreign DNA and for mapping. (C) 2000 F ederation of European Microbiological Societies. Published by Elsevier Scie nce B.V. All rights reserved.