Cellular imitations

Abstract

Synthetic biologists typically construct new pathways within existing cells. While useful, this approach in many ways ignores the undefined but necessary components of life. A growing number of laboratories have begun to try to remove some of the mysteries of cellular life by building life-like systems from non-living component parts. Some of these attempts rely on purely chemical and physical forces alone without the aid of biological molecules, while others try to build artificial cells from the parts of life, such as nucleic acids, proteins, and lipids. Both bottom-up strategies suffer from the complication of trying to build something that remains undefined. The result has been the development of research programs that try to build systems that mimic in some way recognized living systems. Since it is difficult to quantify the mimicry of life, success often times is evaluated with a degree of subjectivity. Herein we highlight recent advances in mimicking the organization and behavior of cellular life from the bottom-up.

Integrating artificial with natural cells to translate chemical messages that direct E. coli behaviour

“…Further, artificial cells can synthesize and release signalling molecules sensed by living cells without exploiting genetically encoded parts3132. The possibility of merging advances with non-genetically encoded and genetically encoded parts may lead to the construction of artificial cells that are better able to imitate natural cellular life3334.…”

Is defining life pointless? Operational definitions at the frontiers of biology

“…135-136). This point is still relevant in current Synthetic Biology, where the lack of clear theoretically grounded means of evaluating the outcomes of experimental efforts in building artificial cells has slowed the advancement of research in the field (Forlin et al 2012).…”

“…Similarly, in some branches of Synthetic Biology definitions play a role in the choice of relevant or interesting biological properties to implement in synthetic systems (Ruiz-Mirazo and Moreno 2013). Moreover, as acknowledged in the literature in Synthetic Biology, the evaluation of results in the design of synthetic cells is particularly problematic in the absence of definitions (see for example, Cronin et al 2006;Forlin et al 2012). 25 In Artificial Life definitions are used, for example, in the selection of the relevant properties of life that should be simulated.…”

Darwinian evolution in a translation-coupled RNA replication system within a cell-like compartment

“…To date, several cellular functions have been reconstructed using simple compounds, such as fatty acids, that may have existed during the prebiotic era [8][9][10][11][12] . Using other approaches, including the semi-synthetic approach 13 and the supramolecular approach 13 , various cellular functions have been reconstituted from purified biological polymers, such as proteins and RNA, in either lipid vesicles or water-in-oil emulsions to determine the conditions sufficient for achieving the target biological functions [14][15][16][17][18] . However, the creation of an artificial cell that harbours the same level of evolutionary ability as natural organisms remains a major challenge.…”