The essential genome of a bacterium

Abstract

Abstract Caulobacter crescentus is a model organism for the integrated circuitry that runs a bacterial cell cycle. Full discovery of its essential genome, including non‐coding, regulatory and coding elements, is a prerequisite for understanding the complete regulatory network of a bacterial cell. Using hyper‐saturated transposon mutagenesis coupled with high‐throughput sequencing, we determined the essential Caulobacter genome at 8 bp resolution, including 1012 essential genome features: 480 ORFs, 402 regulatory sequences and 130 non‐coding elements, including 90 intergenic segments of unknown function. The essential transcriptional circuitry for growth on rich media includes 10 transcription factors, 2 RNA polymerase sigma factors and 1 anti‐sigma factor. We identified all essential promoter elements for the cell cycle‐regulated genes. The essential elements are preferentially positioned near the origin and terminus of the chromosome. The high‐resolution strategy used here is applicable to high‐throughput, full genome essentiality studies and large‐scale genetic perturbation experiments in a broad class of bacterial species.

Keywords

• functional genomics
• next‐generation sequencing
• systems biology
• transposon mutagenesis