Borgs are giant extrachromosomal elements
>  Intriguingly, all Borgs carry large FtsZ-tubulin homologs that may be involved in membrane remodeling or division, and proteins that resemble Major Vault Proteins and the TEP1-like TROVE domain protein that also do not occur in Methanoperedens genomes (Table S5). These are known to form the highly conserved and enigmatic eukaryotic vault organelle, a ribonucleoprotein that has been suggested to be involved in multidrug resistance, nucleo-cytoplasmic transport, mRNA localization, and innate immunity.<p>I can't follow most of this, but the phrase "highly conserved and enigmatic eukaryotic vault organelle" jumped out at me: <a href="https://en.wikipedia.org/wiki/Vault_(organelle)" rel="nofollow">https://en.wikipedia.org/wiki/Vault_(organelle)</a>