title: Recurrent horizontal transfer of bacterial toxin genes to eukaryotes.
abstract: In this work, we report likely recurrent horizontal (lateral) gene transfer events of genes encoding pore-forming toxins of the aerolysin family between species belonging to different kingdoms of life. Clustering based on pairwise similarity and phylogenetic analysis revealed several distinct aerolysin sequence groups, each containing proteins from multiple kingdoms of life. These results strongly support at least six independent transfer events between distantly related phyla in the evolutionary history of one protein family and discount selective retention of ancestral genes as a plausible explanation for this patchy phylogenetic distribution. We discuss the possible roles of these proteins and show evidence for a convergent new function in two extant species. We hypothesize that certain gene families are more likely to be maintained following horizontal gene transfer from commensal or pathogenic organism to its host if they 1) can function alone; and 2) are immediately beneficial for the ecology of the organism, as in the case of pore-forming toxins which can be utilized in multicellular organisms for defense and predation.
authors.affiliation: Department for Molecular Evolution and Development, Center for Organismal Systems Biology, University of Vienna, Vienna, Austria. yehu.moran@univie.ac.at
authors.forename: Yehu
authors.initials: Y
authors.lastname: Moran
authors.forename: David
authors.initials: D
authors.lastname: Fredman
authors.forename: Pawel
authors.initials: P
authors.lastname: Szczesny
authors.forename: Marcin
authors.initials: M
authors.lastname: Grynberg
authors.forename: Ulrich
authors.initials: U
authors.lastname: Technau
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003063:Cnidaria / Q000235:genetics / Q000378:metabolism; D056890:Eukaryota / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D015870:Gene Expression; D022761:Gene Transfer, Horizontal; D008969:Molecular Sequence Data; D010802:Phylogeny; D052899:Pore Forming Cytotoxic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001427:Bacterial Toxins; D052899:Pore Forming Cytotoxic Proteins; C032676:aerolysin