Complete identity and expression of StfZ, the cis-antisense RNA to the mRNA of the cell division gene ftsZ, in Escherichia coli

The global RNA-RNA interactome of Klebsiella pneumoniae unveils a small RNA regulator of cell division

The ubiquitous RNA chaperone Hfq is involved in the regulation of key biological processes in many species across the bacterial kingdom. In the opportunistic human pathogen Klebsiella pneumoniae, deletion of the hfq gene affects the global transcriptome, virulence, and stress resistance; however, the ligands of the major RNA-binding protein in this species have remained elusive. In this study, we have combined transcriptomic, co-immunoprecipitation, and global RNA interactome analyses to compile an inventory of conserved and species-specific RNAs bound by Hfq and to monitor Hfq-mediated RNA-RNA interactions. In addition to dozens of RNA-RNA pairs, our study revealed an Hfq-dependent small regulatory RNA (sRNA), DinR, which is processed from the 3' terminal portion of dinI mRNA. Transcription of dinI is controlled by the master regulator of the SOS response, LexA. As DinR accumulates in K. pneumoniae in response to DNA damage, the sRNA represses translation of the ftsZ transcript by occupation of the ribosome binding site. Ectopic overexpression of DinR causes depletion of ftsZ mRNA and inhibition of cell division, while deletion of dinR antagonizes cell elongation in the presence of DNA damage. Collectively, our work highlights the important role of RNA-based gene regulation in K. pneumoniae and uncovers the central role of DinR in LexA-controlled division inhibition during the SOS response.

RegulonDB v12.0: a comprehensive resource of transcriptional regulation in E. coli K-12

RegulonDB is a database that contains the most comprehensive corpus of knowledge of the regulation of transcription initiation of Escherichia coli K-12, including data from both classical molecular biology and high-throughput methodologies. Here, we describe biological advances since our last NAR paper of 2019. We explain the changes to satisfy FAIR requirements. We also present a full reconstruction of the RegulonDB computational infrastructure, which has significantly improved data storage, retrieval and accessibility and thus supports a more intuitive and user-friendly experience. The integration of graphical tools provides clear visual representations of genetic regulation data, facilitating data interpretation and knowledge integration. RegulonDB version 12.0 can be accessed at https://regulondb.ccg.unam.mx.

Artificial Diploid Escherichia coli by a CRISPR Chromosome-Doubling Technique

Synthetic biology has been represented by the creation of artificial life forms at the genomic scale. In this work, a CRISPR-based chromosome-doubling technique is designed to first construct an artificial diploid Escherichia coli cell. The stable single-cell diploid E. coli is isolated by both maximal dilution plating and flow cytometry, and confirmed with quantitative PCR, fluorescent in situ hybridization, and third-generation genome sequencing. The diploid E. coli has a greatly reduced growth rate and elongated cells at 4-5 µm. It is robust against radiation, and the survival rate after exposure to UV increased 40-fold relative to WT. As a novel life form, the artificial diploid E. coli is an ideal substrate for research fundamental questions in life science concerning polyploidy. And this technique may be applied to other bacteria.