Cloning of the Genes for AF/R1 Pili from Rabbit Enteroadherent Escherichia coli RDEC-1 and DNA Sequence of the Major Structural Subunit
WALTER REED ARMY INST OF RESEARCH WASHINGTON DC
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AFR1 pili on the surface of Escherichia coli RDEC-1 promote attachment of the bacteria to rabbit intestinal brush borders. In order to characterize AFR1 pili and manipulate their expression, we cloned the genes necessary for AFR1 expression determined the size of proteins produced in minicells located the gene encoding the major structural subunit, named AfrA and determined the DNA sequence of afrA as well as the sequence of 700 additional nucleotides upstream of afrA. Two contiguous EcoRI fragments spanning 7.9 kilobases were cloned from the 86-megadalton plasmid of RDEC-1 into vector pUC19 to make plasmid pW1. Bacteria carrying pW1 produced AFR1 pili that were recognized by AFR1-specific antiserum and promoted adherence of bacteria to brush borders prepared from rabbit intestine. Proteins with a molecular weight of 17,000 17K proteins, which was the size of AfrA, as well as 15K, 15.5K, 26K, 28K, and 80K proteins were detected in minicells carrying pW1.