Casitone-dependent transcriptional regulation of theprtP andprtM genes in the natural isolateLactobacillus paracasei subsp.paracasei

Abstract

TheprtP-prtM intergenic region ofLactobacillus paracasei subsp.paracasei BGHN14 was cloned and sequenced. The nucleotide sequence of theprtP-prtM intergenic region in BGHN14, containing divergently orientated P prtP and P prtM promoters, was shorter by 35 bp in comparison with that in lactococci. The nucleotide sequence involved in casitone-dependent transcriptional regulation of the lactococcalprt genes was not found in the BGHN14. The activity of P prtM inL. lactis NZ9000 was very low and insignificantly changed in the presence of casitone, whereas P prtP was completely inactive. WhenL. casei ATCC393T was used as host, both P prtP and P prtM were active and strongly regulated by casitone. The results strongly indicate that the mechanisms of the casitone-dependent regulation of theprt genes in BGHN14 and lactococci are different.