Flagella are large transenvelope nanomachines but how they transit the peptidoglycan in gram-positive bacteria is poorly understood. A recent model...

Bacterial gene expression depends on the coordinated regulation of RNA synthesis, processing, and decay. The conserved RNA degradosome scaffold, Ribonuclease E (RNase E), assembles into phase-separate...

Our understanding of bacterial transcription regulation is largely based on model organisms like Escherichia coli and Bacillus subtilis, yet many of these mechanisms appear absent or divergent in cyanobacteria. These differences limit our fundamental understanding of gene regulation and the applied potential of cyanobacteria in sustainable biomanufacturing. To address this gap, we characterized transcription termination in the model cyanobacterium Synechococcus elongatus PCC 7942. We resolve a longstanding question by showing that intrinsic termination alone cannot account for most termination events in this organism. Pervasive transcript ends lacking intrinsic terminator features and the absence of Rho suggest the existence of novel termination mechanism(s) and highlight a largely unexplored regulatory landscape. Simultaneously, our work expands the repertoire of functionally characterized cyanobacterial intrinsic terminators, offering a new toolkit to fine-tune gene expression using terminators of defined strengths. These findings pave the way for more predictable and powerful applications of cyanobacteria in green biotechnology.

Polyphosphate (polyP) is a conserved inorganic polymer traditionally viewed as a stress-induced phosphate and energy reserve. In cyanobacteria, however, polyP granules are constitutively present and frequently observed in proximity to carboxysomes, the bacterial microcompartments that mediate CO2 fixation. Here we show that polyP functions as a spatially organized regulator of the photosynthetic cytoplasm in Synechococcus elongatus. PolyP granules localize to the nucleoid and are periodically arranged along the cell axis, independently of the McdAB carboxysome positioning system. Despite this independence, polyP and carboxysomes associate non-randomly, and this association is enhanced when active carboxysome positioning by the McdAB system is disrupted. Loss of polyP synthesis leads to nucleoid expansion, an increased number of smaller carboxysomes with high mobility, and severe defects in growth under ambient CO2. Perturbation of polyP turnover further reveals structural connections to both carboxysomes and thylakoid membranes. Together, these findings identify polyP as an architectural integrator that couples chromosome organization, metabolic compartmentalization, and photosynthetic fitness. ### Competing Interest Statement The authors have declared no competing interest. National Institute of General Medical Sciences, https://ror.org/04q48ey07, R01-GM144731, R35-GM152128 Howard Hughes Medical Institute

Bacterial ribonucleoprotein bodies are dynamic biomolecular condensates that play roles in RNA metabolism. Here, Ortiz-Rodríguez et al. show that, under stress, these condensates shift from a liquid s...

Lucy Shapiro

Lucy Shapiro entered biology “like a bolt of lightning.” A groundbreaking scientist, mentor, drug developer and advocate for science communication is recognized for a lifetime of achievements.

The RNA-binding protein CsrA switches from upregulation to downregulation of virulence genes in bacteria through unclear mechanisms. Here, the authors show that the switch between promoting and repres...

The advent of clonal multicellularity is a critical evolutionary milestone, seen often in eukaryotes, rarely in bacteria, and only once in archaea. We show that uniaxial compression induces clonal mul...