Two tales about phage-inducible chromosomal islands

Thursday 9 May 2019, 1.00PM

Speaker(s): Professor Jose R Penades, University of Glasgow

Bacteria are successful as commensal organisms or pathogens in part because they adapt rapidly to selective pressures. Mobile genetic elements (MGEs) play a central role in this adaptation process and are a means to transfer genetic information (DNA) among and within bacterial species.

During the last years we have identified and characterised a novel family of mobile pathogenicity islands, the phage-inducible chromosomal islands (PICIs), which are clinically important because they carry and disseminate virulence and antibiotic-resistance genes. In addition to their role in bacterial evolution, the PICIs have a sophisticated life cycle that involves induction by a helper phage. Once this occurs, PICIs hijack the phage machinery for their own packaging, which ensures their widespread dissemination. In this talk we will report the existence of a hitherto unrecognised attribute of the PICIs that allows their promiscuous spread in nature.

We will describe that a subset of PICIs has evolved a fascinating strategy that promotes their high transfer by pirating other PICIs, highlighting these elements as one of nature’s most intriguing subcellular parasites. Moreover, in this talk we will also decipher how the Gram-negative PICIs hijack the phage machinery for their own specific packaging, and how they block phage reproduction. These results will introduce new paradigms in the understanding of the biology of pathogenicity islands and therefore of bacterial biology and evolution.

Location: Dianna Bowles Lecture Theatre (K018)