RESUMO
Recent advances in DNA synthesis technology have enabled the construction of novel genetic pathways and genomic elements, furthering our understanding of system-level phenomena. The ability to synthesize large segments of DNA allows the engineering of pathways and genomes according to arbitrary sets of design principles. Here we describe a synthetic yeast genome project, Sc2.0, and the first partially synthetic eukaryotic chromosomes, Saccharomyces cerevisiae chromosome synIXR, and semi-synVIL. We defined three design principles for a synthetic genome as follows: first, it should result in a (near) wild-type phenotype and fitness; second, it should lack destabilizing elements such as tRNA genes or transposons; and third, it should have genetic flexibility to facilitate future studies. The synthetic genome features several systemic modifications complying with the design principles, including an inducible evolution system, SCRaMbLE (synthetic chromosome rearrangement and modification by loxP-mediated evolution). We show the utility of SCRaMbLE as a novel method of combinatorial mutagenesis, capable of generating complex genotypes and a broad variety of phenotypes. When complete, the fully synthetic genome will allow massive restructuring of the yeast genome, and may open the door to a new type of combinatorial genetics based entirely on variations in gene content and copy number.
Assuntos
Cromossomos Artificiais de Levedura/genética , Engenharia Genética/métodos , Saccharomyces cerevisiae/genética , Biologia Sintética/métodos , Sítios de Ligação Microbiológicos/genética , Evolução Molecular Direcionada/métodos , Dosagem de Genes/genética , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Aptidão Genética/genética , Genoma Fúngico/genética , Genótipo , Haploidia , Dados de Sequência Molecular , Mutagênese/genética , Fenótipo , RNA Fúngico/análise , RNA Fúngico/genética , Saccharomyces cerevisiae/classificaçãoRESUMO
The innate immune system uses pattern recognition receptors (PRRs) to sense invading microbes and initiate a rapid protective response. PRRs bind and are activated by structural motifs, such as nucleic acids or bacterial and fungal cell wall components, collectively known as pathogen-associated molecular patterns. PRRs that recognize pathogen-derived nucleic acids are present in vesicular compartments and in the cytosol of most cell types. Here, we review recent studies of these cytosolic sensors, focusing on the nature of the ligands for DNA-dependent activator of interferon (DAI)-regulatory factors, absent in melanoma 2 (AIM2), and the retinoic acid-inducible gene I-like helicase (RLH) family of receptors, the basis of ligand recognition and the signaling pathways triggered by the activation of these receptors. An increased understanding of these molecular aspects of innate immunity will guide the development of novel antiviral therapeutics.
