José R Penadés
José R Penadés, after finishing his Veterinary Medicine Degree in Zaragoza (Spain), obtained his PhD in Valencia, in the Instituto de Investigaciones Citológicas, characterising the molecular basis of the Goodpasture syndrome, an autoimmune human disease. Research in Penadés lab has focused for the last decade into the molecular basis of bacterial virulence, using Staphylococcus aureus as a model, with a major focus on the mechanisms underlying the transfer of different mobile genetic elements (MGEs) involved in pathogenesis. We have described that in S. aureus the genes for some superantigen toxins and for other virulence factors, especially those involved in host adaptation, are borne by a family of mobile pathogenicity islands (SaPIs). SaPIs represent the first pathogenicity island identified in staphylococci and the first for which mobility has been shown. During the last few years, we have deciphered the fascinating mechanisms involved in the transfer of these MGEs. SaPIs are 15 kb or more in size, are excised, caused to replicate, and then encapsidated with high efficiency after induction by certain staphylococcal phages. This results in an extremely high frequency of transduction, both intra- and inter-generically. Not surprisingly, such elements are not confined to the staphylococci and we have recently identified a large set of similar elements in Gram-positive and Gram-negative bacteria, supporting the existence of a novel family of MGEs that we have defined as Phage-Inducible Chromosomal Islands (PICIs). To characterise the molecular biology of this novel and widespread family of MGEs, the major aims of our laboratory are to understand the mechanisms of PICI transfer, and the roles of the PICI elements in virulence. Overall, our recent research findings suggest the existence of previously unrecognised mechanisms of gene transfer, involving both this novel family of MGEs as well as their inducing phages.