Figure 1

In vivo transcriptional fusion by integration of a promoterless cat gene into the chromosome of a naturally transformable streptococcus. A promoterless cat gene is ligated in vitro to random chromosomal fragments, using a restriction site a few base pairs upstream of its translation initiation codon (a). The ligation mixture is then used to transform the recipient strain (b), and the homologous sequences allow chromosomal integration of the promoterless cat gene (c). By this process, the cat gene is integrated into the chromosome between two direct repeats. Since some of the chromosomal fragments contain promoters (P), it is possible to obtain expression of the promoterless cat gene after in vivo transcriptional fusion with resident chromosomal promoters.