title: Transcription of the yop regulon from Y. enterocolitica requires trans acting pYV and chromosomal genes.
abstract: Virulent Y. enterocolitica strains restrict their growth at 37 degrees C, in rich medium deprived of calcium. This property, called calcium dependency, correlates with pathogenicity. It is conditioned by a 70 kb plasmid called pYV. The analysis of calcium independent (Cl) insertion mutants defined a 20 kb region called the calcium region. This region contains at least three transcription units called virA, B and C. In growth restriction conditions, Y. enterocolitica releases and inserts in its outer-membrane several pYV encoded proteins (POMPs). By transposition mutagenesis using a mini-Mu dlac element, we localized plasmid genes encoding POMPs of 84, 51, 30 and 25 kDa. These genes appear to be scattered on pYV, outside the calcium region and to constitute a regulon. Transcription of these yop genes increased by factors of 3.5 (yop84) to 200 (yop51) when temperature was shifted from 25 to 37 degrees C. On the contrary, calcium had only a moderate effect. Transcription was also dependent on the culture medium and on a trans-acting factor encoded by the calcium region. One Cl double mutant severely affected in transcription of yop51 defined a new locus called virF in the calcium region of pYV. Transcription of the yop genes was very poor in E. coli K12, even in the presence of a fully functional calcium region.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000502:physiology*; D003001:Cloning, Molecular; D005796:Genes; D005798:Genes, Bacterial; D005809:Genes, Regulator; D005816:Genetic Complementation Test; D009154:Mutation; D010957:Plasmids; D014158:Transcription, Genetic; D015008:Yersinia enterocolitica / Q000235:genetics* / Q000254:growth & development
chemical_list: D001426:Bacterial Proteins