The Global Landscape of Transcription Initiation During the Caulobacter Cell Cycle [mapping]

The Caulobacter cell cycle includes in an asymmetric cell division that is driven by a core regulatory circuit comprised of 4 transcription factors (DnaA, GcrA, CtrA, and SciP) and a DNA methyltransferase (CcrM). Using a modified global 5' RACE protocol we mapped 2,726 transcriptional start sites (TSS) in the 4mb Caulobacter genome and identified 586 cell cycle-regulated TSS. The core cell cycle circuit directly controls about 55% of cell cycle-regulated TSS by integrating multiple regulatory inputs within at least 322 promoters, providing a large number of transcription profiles from a small number of regulatory factors. Here, we identified previously unknown features of the core cell cycle circuit, including antisense TSS within dnaA and ctrA, plus newly identified TSS for ctrA and ccrM. Altogether, we identified 615 antisense TSS plus 241 genes that are transcribed from multiple TSS. The multiple TSS in the same promoter region often exhibit different cell cycle activation timing, These novel features of the global transcript profile add significant insight to the system architecture of the Caulobacter cell cycle regulatory circuit. Overall design: Global 5' RACE was performed to map Transcription Start Sites in the Caulobacter NA1000 genome