Massive expansion of Ubiquitination-related gene families within the Chlamydiae.
Bottom Line: We discovered that the largest gene families within the phylum are the result of rapid gene birth-and-death evolution.A heterologous type III secretion system assay suggests that these proteins function as effectors manipulating the host cell.Gene birth-and-death evolution in concert with genomic drift might represent a previously undescribed mechanism by which isolated bacterial populations diversify.
Affiliation: Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.Show MeSH
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Mentions: To gain a broader overview of the occurrence of F-box/F-box-like and BTB/POZ domains among other prokaryotes and eukaryotes, we extracted domain abundance data from Pfam (Finn et al. 2013) and included the current counts for the Chlamydiae genomes present in this study (fig. 6). This revealed a striking pattern that the few bacterial groups encoding proteins with F-box and BTB domains are almost exclusively amoeba-associated organisms. These include members of the Legionellales (Gammaproteobacteria), the Rickettsiales (Alphaproteobacteria), and the amoeba symbiont Amoebophilus asiaticus (Bacteroidetes). When the number of F-box proteins is normalized against the total number of species in a given taxon, the Chlamydiae lead in the number of F-box proteins found in bacteria and even harbor more than several lineages of eukaryotes including the Amoebozoa. For the BTB proteins, the Chlamydiae appear to be the only bacterial lineage that harbors this domain. It is intriguing that many of the large double-stranded DNA viruses, namely the amoeba-infecting giant viruses, contain many proteins with an F-box or BTB domain.Fig. 6.
Affiliation: Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.