Intramers as promising new tools in functional proteomics.

Aptamers are valuable tools for studying numerous aspects of biological processes, opening up new experimental opportunities to analyse the function of a wide range of cellular molecules. Functional RNA molecules can be rapidly selected in vitro from complex combinatorial mixtures of different sequences. Recently, it was shown that in vitro selection processes can be automated: the first generation selection robots will soon mean aptamers for several targets can be isolated in parallel within days rather than weeks. Aptamers not only exhibit highly specific molecular recognition properties but are also able to modulate the function of their cognate targets in a highly specific manner by agonistic or antagonistic mechanisms. These properties prompted the development of novel technologies to exploit the use of aptamers to modulate distinct functions of biological targets. Recent controlled expression of aptamers inside cells demonstrated their impressive potential as rapidly generated intracellular inhibitors of biomolecules. Intracellularly applied aptamers are also called 'intramers'. Here we discuss recent developments and strategies for intramer-based technologies that have the potential to greatly facilitate characterisation of unknown protein functions in the context of their natural expression status in vivo. Thus, intramer-based technologies offer many promising applications in functional genomics, proteomics and drug discovery.