Genes for CS2 pili of enterotoxigenic Escherichia coli and their interchangeability with those for CS1 pili

We have cloned and sequenced the DNA needed for production of CS2 pili in Escherichia coli K-12. The four open reading frames, cotB, cotA, cotC, and cotD, show homology with the genes needed for production of CS1 and CFA/I pili, which are also found on enterotoxigenic E. coli associated with human diarrheal disease. We also report that CotA plus CotB interact with the CS1 gene products CooC and CooD to form pili that can be visualized by electron microscopy and, conversely, that the CS1 gene products CooA and CooB interact with CotC and CotD to form pili.