A MOLECULAR PREDATOR AND ITS PREY - COUPLED ISOTHERMAL AMPLIFICATION OF NUCLEIC-ACIDS

Background: A novel approach to the study of in vitro evolution is pro vided by the investigation of continuous, functionally coupled, amplif ying systems. To date, in vitro evolution experiments have focused on issues of mutation and selection. Our work contributes to the new fiel d of in vitro molecular ecology studies in which detailed information about the relationship between sequence changes and molecular interact ions is obtained. Predator-prey systems are interesting in this contex t both in terms of evolutionary limits and in terms of the potential k inetic properties of oscillation and spatial pattern formation. Such m olecular predator-prey models can be extended to a further negative-in teraction mode, viral-host molecular evolution. Results: A simple, non functional predator-prey system based on the self-sustained sequence r eplication reaction is proposed. Coupling within the system is achieve d using the single-stranded DNA intermediate of one cycle, the prey cy cle, as primer for the second one, the predator cycle. Hybridization j y complementary base pairing is the second order reaction step underly ing the predation. Single steps of the whole reaction system have been investigated by radiolabeling. Each isolated subsystem operates accor ding to the proposed reaction scheme, and evidence for an efficient co upling of both subsystems according to the proposed mechanism was foun d. Conclusions: Simple, interacting model systems based on nucleic aci ds can be designed and constructed for the study of coevolution, The r esults of studies such as the one described here will provide a basis for the construction of coupled systems of ribozymes, from which point the engineering of catalytic units for applications in biotechnology is feasible.