Ramifications of the diverse mRNA patterns inAcanthamoeba royreba

Free-living amoebae are distributed worldwide and can be found in a variety of environments. While most Acanthamoebae have been isolated from soil and water, A. royreba and A. culbertsoni were isolated from mammalian cell cultures. A. royreba’s isolation from placental and tumoral tissue, its unusual ability to grow in mammalian cell culture media at 35°C, and the presence of a primitive centriole, prompted us to investigate the potential for mammalian information in A. royreba. While some soil amoeba contain small amounts of fungal and bacterial information, presumably from the microbes they phagocytosed, the informational content of A. royreba, in some instances, was very different with > 70% of the mRNA being non-amoebic. Here we show that the proteins and mRNA content associated with A. royreba are extremely diverse and represent multiple Kingdoms, Orders, Phyla, and Genera from around the globe. The information in A. royreba, such as placental proteins from numerous mammals, the preponderance of non-amoebic mRNA, and its ability to tolerate harsh environments including Megarad irradiation, leads to a discussion regarding the possible role of this amoebae as an immunological gatekeeper protecting fetal or malignant tissue from destruction and its potential as a vehicle for panspermia.