title: Protein-mediated selective enclosure of early replicators inside of membranous vesicles: first step towards cell membranes.
abstract: Containment in cell membranes is essential for all contemporary life, and apparently even the earliest life forms had to be somehow contained. It has been postulated that random enclosure of replicating molecules inside of spontaneously assembled vesicles would have formed the initial cellular ancestors. However, completely random re-formation or division of such primitive vesicles would have abolished the heritability of their contents, nullifying any selective advantage to them. We propose that the containment of the early replicators in membranous vesicles was adopted only after the invention of genetically encoded proteins, and that selective enclosure of target molecules was mediated by specific proteins. A similar containment process is still utilised by various RNA- and retroviruses to isolate their replication complexes from the host's intracellular environment. Such selective encapsulation would have protected the replicators against competitor and parasitic sequences, and provided a strong positive selection within the replicator communities.
authors.affiliation: Laboratory of Plant Physiology and Molecular Biology, University of Turku, Finland.
authors.forename: Tiina
authors.initials: T
authors.lastname: Laiterä
authors.forename: Kirsi
authors.initials: K
authors.lastname: Lehto
mesh_terms: D002451:Cell Compartmentation; D019143:Evolution, Molecular; D005227:Fatty Acids / Q000378:metabolism; D008566:Membranes / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D000069497:Origin of Life; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics / Q000378:metabolism; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism; D053835:Unilamellar Liposomes; D014779:Virus Replication
chemical_list: D005227:Fatty Acids; D011506:Proteins; D013501:Surface-Active Agents; D053835:Unilamellar Liposomes; D012313:RNA