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Experimental approach to minimal cells PDF Print E-mail

The main predicate of modern science about the origin of life on Earth, is that life originated from the inanimate matter through a very long series of reactions yielding structures of increasing complexity and functionalities, up to the formation of protocells that could eventually self-reproduce. This means that in order to reproduce in the laboratory minimal life forms, we have to implement the synthesis of “minimal cells”, where minimal means that they contain the minimal and sufficient complexity to yield cellular life. Comprehensibly, then, compartments such as liposomes have been considered the best models for primitive cells (protocells). This lecture aims at discussing the possible pathway to achieve such the laboratory construction of minimal cells.

It will be preliminarily shown that the bottom up approach to life is made difficult, or impossible, by the fact that our proteins and the other functional macromolecular sequences are the products of contingency –and we do not know the original conditions and how they changed during the biogenesis. However, to tackle in the lab the construction of minimal cells, another approach can be used (by some called top-down approach). This consists in inserting in liposomes extant genes and enzymes, chosen so as to be the minimal and sufficient number for inducing the minimal cellular life. This would be an absolute minimal genome that would give indications on the structure of the very early cells.

The methods to incorporate enzymes and genes into liposomal compartments will be presented, with selective examples of complex molecular biology reactions. Then, I will outline the attempts to incorporate ribosomes and the whole protein synthetic apparatus at the aim of expressing proteins inside liposomes. In particular it will be shown how the incorporation of a kit of 36 enzymes plus ribosomes (the so-called “*PURE SYSTEM” of prof. Ueda in Japan) into liposomes permits the expression of proteins, including membrane proteins, inside the compartments. The final target of the “minimal cell” project is to obtain a self-reproducing system, which is under study. The difficulties and implications of this research will be discussed.

Last Updated on Tuesday, 22 April 2008 12:53