Maximizing transcription of nucleic acids with efficient T7 promoters
Thomas Conrad, Izabela Plumbom, Maria Alcobendas, Ramón Vidal, Sascha Sauer
Abstract
Abstract In vitro transcription using T7 bacteriophage polymerase is widely used in molecular biology. Here, we use 5′RACE-Seq to screen a randomized initially transcribed region of the T7 promoter for cross-talk with transcriptional activity. We reveal that sequences from position +4 to +8 downstream of the transcription start site affect T7 promoter activity over a 5-fold range, and identify promoter variants with significantly enhanced transcriptional output that increase the yield of in vitro transcription reactions across a wide range of template concentrations. We furthermore introduce CEL-Seq + , which uses an optimized T7 promoter to amplify cDNA for single-cell RNA-Sequencing. CEL-Seq+ facilitates scRNA-Seq library preparation, and substantially increases library complexity and the number of expressed genes detected per cell, highlighting a particular value of optimized T7 promoters in bioanalytical applications.