The various motifs that stimulate RT in eukaryotic cells have been previously classified by Beier and Grimm and by Harrell et al. (34, 81) . Beier and Grimm define the classes Type I (generally UAG-CAA-UYA; includes tobamovirus replicase, and benyvirus and pomovirus CP extension), Type II (generally UGA-CGG or UGA-CUA; includes alphavirus replicase, tobravirus, pecluvirus, furovirus and pomovirus replicase, and furovirus CP extension), and Type III (generally UAG-G, plus a compact pseudoknot in gammaretroviruses and possible but as yet relatively uncharacterized structures in the luteoviruses and tombusviruses). There are exceptions to the rule (e.g. enamovirus UGA-G, various pomovirus cases with atypical stop codons, and so on). One reason for this may be that the required level of RT may vary between different viruses, and may also be modulated by other sequence elements (e.g. 5 0 nucleotide and/or amino acid context) so that, in certain cases, deviations from one of the 'canonical' RT motifs may be tolerated. With this proviso, our results suggest that the definition of the Type II motif should, in general though perhaps not ubiquitously, be modified to include a 3 0 RNA structure component. Our discovery in alphaviruses and phylogenetically supported predictions for many plant viruses and the Drosophila gene kelch, together with the small number of previously identified cases of structure-stimulated RT, now suggest that 3 0 RNA structures as a component of efficient RT cassettes in eukaryotes (especially those that lack a CAR-YYA tobamovirus-like stimulator), rather than being exceptional, may in fact be the norm. Antigen-expressing immunostimulatory liposomes as a genetically programmable synthetic vaccine Liposomes are versatile (sub)micron-sized membrane vesicles that can be used for a variety of applications, including drug delivery and in vivo imaging but they also represent excellent models for artificial membranes or cells. Several studies have demonstrated that in vitro transcription and translation can take place inside liposomes to obtain compartmentalized production of functional proteins within the liposomes (Kita et al. in Chembiochem 9(15):2403–2410, 2008; Moritani et al.in FEBS J, 2010; Kuruma et al. in Methods Mol Biol 607:161–171, 2010; Murtas et al. in Biochem Biophys Res Commun 363(1):12–17, 2007; Sunami et al. in Anal Biochem 357(1):128–136, 2006; Ishikawa et al. in FEBS Lett 576(3):387–390, 2004; Oberholzer et al. in Biochem Biophys Res Commun 261(2):238–241, 1999). Such a minimal artificial cell-based model is ideal for synthetic biology based applications. In this study, we propose the use of liposomes as artificial microbes for vaccination. These artificial microbes can be genetically programmed to produce specific antigens at will. To show proof-of-concept for this artificial cell-based platform, a bacterial in vitro transcription and translation system together with a gene construct encoding the model antigen β-galactosidase were entrapped inside multilamellar liposomes. Vaccination studies in mice showed that such antigen-expressing immunostimulatory liposomes (AnExILs) elicited higher specific humoral immune responses against the produced antigen (β-galactosidase) than control vaccines (i.e. AnExILs without genetic input, liposomal β-galactosidase or pDNA encoding β-galactosidase). In conclusion, AnExILs present a new platform for DNA-based vaccines which combines antigen production, adjuvanticity and delivery in one system and which offer several advantages over existing vaccine formulations. Synthetic biology is a rapidly emerging interdisciplinary research field that aims to construct new biological parts and systems with new functionalities through a process of engineering and standardization. Vaccines may also benefit from a synthetic biology-based design. With vaccination the aim is to delude the immune system with an antigenic formulation to make it believe it is dealing with a natural infection, however, without causing illness. At present, the majority of vaccines on the market consist of attenuated or inactivated pathogens. Although effective, these systems are poorly defined, suffer from batch-to-batch variation and can only be used for pathogens that can be readily cultivated in the lab at scales that permit vaccine production. Moreover, as the ratio of antigenic compounds within the pathogen is more-or-less fixed, there is poor control over the direction against which antigenic compound an immune reaction will be evoked. The bottom-up design of vaccines which consist of well-defined antigenic compounds (e.g. proteins or nucleic acids) offers better control over the evoked immune reaction, however, the design of such vaccines is often empirical and in general yields vaccines that are poorly immunogenic and rely on adjuvants in order to be effective. Moreover, most vaccine production schemes are rather time-consuming, and therefore not suitable for rapid response intervention, for example, to prevent the pandemic spread of a new influenza strain in the human population.