RESUMEN
A crucial step towards engineering biological systems is the ability to precisely tune the genetic response to environmental stimuli. In the case of Escherichia coli inducible promoters, our incomplete understanding of the relationship between sequence composition and gene expression hinders our ability to predictably control transcriptional responses. Here, we profile the expression dynamics of 8269 rationally designed, IPTG-inducible promoters that collectively explore the individual and combinatorial effects of RNA polymerase and LacI repressor binding site strengths. We then fit a statistical mechanics model to measured expression that accurately models gene expression and reveals properties of theoretically optimal inducible promoters. Furthermore, we characterize three alternative promoter architectures and show that repositioning binding sites within promoters influences the types of combinatorial effects observed between promoter elements. In total, this approach enables us to deconstruct relationships between inducible promoter elements and discover practical insights for engineering inducible promoters with desirable characteristics.
Asunto(s)
Isopropil Tiogalactósido/farmacología , Lógica , Regiones Promotoras Genéticas , Sitios de Unión , Fenómenos Biofísicos , ARN Polimerasas Dirigidas por ADN/metabolismo , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Fluorescencia , Genes Reporteros , Mutación/genética , Regiones Operadoras Genéticas/genética , Unión Proteica , Reproducibilidad de los Resultados , Termodinámica , Factores de Transcripción/metabolismoRESUMEN
Mycobacteriophages Deby, LaterM, LilPharaoh, Paola, SgtBeansprout, and Sulley were isolated from soil using Mycobacterium smegmatis mc2155. Genomic analysis indicated that they belong to subclusters K1 and K5. Their genomic architectures are typical of cluster K mycobacteriophages, with most variability occurring on the right end of the genome sequence.
