Cloning, bioinformatics study and evaluation expression of gene of enterotoxigenic Escherichia coli CFA/I major subunit (CfaB)

Enterotoxigenic Escherichia coli (ETEC) is the main cause of diarrhea in children in developing countries and also in travelers to these areas. ETEC attaches to host cells via filamentous bacterial surface structures, known as colonization factors. Epidemiological studies suggest that the prevalence of CFA/I is higher than other colonization factors. CFA expressed by ETEC and so represents an important component of any vaccine. Investigation supposed that CfaB as a major subunit of fimbriae is an appropriate candidate for vaccine preparation. In the present study we investigated cloning and expression of CfaB.

In this descriptive study, information about CfaB gene was obtained from gene bank and appropriate primers were designed accordingly. Genomic PCR reaction was performed and its product (CfaB gene) was cloned into pTZ57R/T cloning vector and then subcloned pET28a expression vector. CfaB gene expression was evaluated.

Cloning was confirmed by using restriction enzyme and sequencing. Expression of recombinant protein was determined in different conditions (time, media, and host), but native gene inserted in pET28a was not expressed.

Native gene employs tandem rare codon which can reduce the efficiency of expression.