A bifunctional Streptomyces-E. coli promoter-probe vector.

A bifunctional Streptomyces-E. coli promoter probe vector, pULJA30, has been developed to isolate and characterize nucleotide sequences involved in transcription initiation and regulation. The vector is derived from plasmid pIJ486, carries the pIJ101 replicon and utilizes the promoterless aminoglycoside phosphotransferase (neo) as indicator gene. Important features of the new vector include: wide Streptomyces host range and as high a plasmid copy number as the parental pIJ486, an upstream transcriptional terminator (toop) and a polylinker sequence with unique sites for BamHI and BglII for flexible cloning, fragment re-isolation and direct sequencing of promoter-active inserts. pULJA30 also has an E. coli replicon (from pBR322) and the possibility of selection in Streptomyces and E. coli by using the tsr, neo and bla genes, which makes it very convenient to test the comparative functionality of Streptomyces promoters in E. coli.