The cyclic AMP receptor protein (CRP) controls expression of the ferric uptake regulator (Fur) in Yersinia pestis

Yersinia pestis, the causative agent of plague, is one of the most dangerous pathogens in the world. Both the cyclic AMP receptor protein (CRP) and ferric uptake regulator (Fur) are global regulators that control the expression of a great deal of genes involved in a variety of cellular functions in Y. pestis. In this work, two CRP box-like deoxyribonucleic acid (DNA) sequences were detected in the upstream DNA region of fur, suggesting that the transcription of fur might be directly regulated by CRP in Y. pestis. Thus, transcriptional regulation of fur by CRP was investigated by primer extension, quantitative real-time PCR, LacZ fusion, and electrophoretic mobility shift assays. The results demonstrated that CRP was able to bind the regulatory DNA region of fur to activate its transcription. The data presented here not only suggested that the CRP and Fur regulons were bridged together via the direct regulation of fur by CRP, but also provided us a deeper understanding of the transcriptional regulation of fur in Y. pestis.