Novel organisation and regulation of the pic promoter from enteroaggregative and uropathogenic Escherichia coli

Munirah M Alhammadi, Rita E Godfrey, Joseph O Ingram, Gurdamanjit Singh, Camilla L Bathurst, Stephen J W Busby, Douglas F Browning

Research output: Contribution to journalArticlepeer-review


The serine protease autotransporters of the Enterobacteriaceae (SPATEs) are a large family of virulence factors commonly found in enteric bacteria. These secreted virulence factors have diverse functions during bacterial infection, including adhesion, aggregation and cell toxicity. One such SPATE, the Pic mucinase (protein involved in colonisation) cleaves mucin, allowing enteric bacterial cells to utilise mucin as a carbon source and to penetrate the gut mucus lining, thereby increasing mucosal colonisation. The pic gene is widely distributed within the Enterobacteriaceae, being found in human pathogens, such as enteroaggregative Escherichia coli (EAEC), uropathogenic E. coli (UPEC) and Shigella flexneri 2a. As the pic promoter regions from EAEC strain 042 and UPEC strain CFT073 differ, we have investigated the regulation of each promoter. Here, using in vivo and in vitro techniques, we show that both promoters are activated by the global transcription factor, CRP (cyclic AMP receptor protein), but the architectures of the EAEC and the UPEC pic promoter differ. Expression from both pic promoters is repressed by the nucleoid-associated factor, Fis, and maximal promoter activity occurs when cells are grown in minimal medium. As CRP activates transcription in conditions of nutrient depletion, whilst Fis levels are maximal in nutrient-rich environments, the regulation of the EAEC and UPEC pic promoters is consistent with Pic's nutritional role in scavenging mucin as a suitable carbon source during colonisation and infection.

Original languageEnglish
Pages (from-to)1393-1406
Number of pages14
Issue number1
Early online date16 Aug 2022
Publication statusPublished - Dec 2022

Bibliographical note

© 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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