Abstract Bacterial regulatory small RNAs (sRNAs) are integral components of posttranscriptional control, shaping environmental adaptation, metabolic homeostasis, and virulence. Advances in transcriptomics and RNA technologies have greatly expanded the repertoire of bacterial sRNAs and revealed their extensive roles in posttranscriptional regulatory networks. This review provides an updated framework for the biogenesis of bacterial sRNAs and their regulatory roles within posttranscriptional networks. Crucially, we describe the regulatory pathways controlling sRNA expression, including environmental signal sensing and regulation mediated by σ factors and transcription factors, to illustrate how sRNAs respond dynamically to changing conditions. Expanding beyond expression control, we further discuss the diverse roles of sRNA-mediated regulation in metabolic adaptation, stress responses, and bacterial virulence, emphasizing their importance in linking environmental changes to cellular phenotypes. Concurrently, we review current experimental and computational methods used for sRNA discovery and target identification. Overall, this review provides an integrated perspective on how bacterial sRNAs connect environmental sensing with adaptive cellular responses and highlights the broader significance of RNA-mediated regulation in bacterial physiology.
Zhengkai Yi, Xingning Xiao, Likou Zou et al.· FEMS Microbiology Reviews· 0 citations
The development of multicellular organisms relies on the precise establishment and stable inheritance of cell type-specific transcriptional programs without changes to the underlying DNA sequence. Polycomb group (PcG) proteins are evolutionarily conserved epigenetic repressors that govern developmental gene expression by assembling into multiprotein complexes to establish robust and spatiotemporally restricted transcriptional silencing. Since their discovery through the classic Polycomb mutant phenotype in Drosophila melanogaster, PcG proteins have become a central paradigm for understanding epigenetic regulation during animal development. Here, we synthesize current knowledge of the molecular composition and functional organization of the core Polycomb repressive complexes (PRC1 and PRC2) and the accessory complexes PhoRC, PR-DUB, and dRAF, with particular emphasis on canonical hierarchical recruitment and emerging noncanonical regulatory mechanisms of Polycomb-mediated gene repression. We further summarize the dynamic roles of PcG proteins across the Drosophila life cycle, from embryonic patterning and larval organogenesis to metamorphic transition and adult tissue homeostasis. By integrating recent advances from Drosophila studies, this review provides a comprehensive overview of the molecular mechanisms and developmental functions of PcG proteins while highlighting future directions for investigating the conserved epigenetic mechanisms governing metazoan development.
