The surface-located YopN protein is involved in calcium signal transduction in Yersinia pseudotuberculosis.
The low-calcium response (lcr) is strongly conserved among the pathogenic Yersinia species and is observed when the pathogen is grown at 37 degrees C in Ca(2+)-depleted medium. This response is characterized by a general metabolic downshift and by a specific induction of virulence-plasmid-encoded yop genes. Regulation of yop expression is exerted at transcriptional level by a temperature-regulated activator and by Ca(2+)-regulated negative elements. The yopN gene was shown to encode a protein (formerly also designated Yop4b) which is surface-located when Yersinia is grown at 37 degrees C. yopN was found to be part of an operon that is induced during the low-calcium response. Insertional inactivation of the yopN gene resulted in derepressed transcription of yop genes. A hybrid plasmid containing the yopN gene under the control of the tac promoter fully restored the wild-type phenotype of the yopN mutant. Thus the surface-located YopN somehow senses the calcium concentration and transmits a signal to shut off yop transcription when the calcium concentration is high.
Forsberg
A
A
Department of Cell and Microbiology, National Defence Research Establishment, Umeå, Sweden.
Viitanen
A M
AM
Skurnik
M
M
Wolf-Watz
H
H
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism*; D004252:DNA Mutational Analysis; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D015151:Immunoblotting; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000502:physiology; D015183:Restriction Mapping; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic; D015011:Yersinia pseudotuberculosis / Q000378:metabolism* / Q000472:pathogenicity
D001426:Bacterial Proteins; D008565:Membrane Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C070015:YopN protein, Yersinia; D002118:Calcium