Protein-mediated Selective Enclosure of Early Replicators Inside of Membranous Vesicles: First Step Towards Cell Membranes
- 145 Downloads
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.
KeywordsOrigin of life Amphiphiles Fatty acids Vesicles Selective encapsulation Defence against parasitic sequences
We wish to thank the anonymous referee for his very profound questions and suggestions, which have essentially helped to clarify and focus this manuscript.
- Baross JA, Hoffman SE (1983) Submarina hydrothermal vents and associated gradient environments as sites for the origin and evolution of life. Orig Life 15:327–345Google Scholar
- Lincoln TA, Joyce GF (2009) Self-sustained replication of an RNA enzyme. Science 323:1229–1232Google Scholar
- Nomura SM, Yoshikawa Y, Yoshikawa K, Dannenmuller O, Chasserot-Golaz S, Ourrisson G, Nakatani Y (2001) Towards proto-cells: “primitive” lipid vesicles encapsulating giant DNA and its histone complex. Chem Biochem 6:457–459Google Scholar
- Zubay G (2000) Orgins of life on the earth and in the cosmos, 2nd edn. Academic, San Diego, CA, p 347Google Scholar