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Establishing a model to study the regulation of the lactose operon in Lactobacillus casei
M J Gosalbes1, V Monedero, C A Alpert
1Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Polígono de la Coma sln, Burjasot, Valencia, Spain.
Abstract:
The chromosomally encoded lactose-specific phosphoenol pyruvate-dependent phosphotransferase system (PTS) has been investigated in Lactobacillus casei ATCC 393 [pLZ15-] and it was considered an excellent system to study the regulation of the lactose operon. This chromosomal operon has been cloned and sequenced, being 99% homologous to that encoded on the plasmid pLZ64. Expression of the lactose operon in different mutants of L. casei ATCC 393 [pLZ15-] and primer extension analysis revealed that it is subject to a dual regulation: (i) glucose repression possibly mediated by CcpA and PTS elements, and (ii) induction by lactose through transcriptional antitermination.