Vol 86, No 6 (2025)

RNA-protein granules are dynamic, membrane-less organelles found in the nucleus and cytoplasm of cells across nearly all organisms, from the unicellular to the multicellular. They are complex assemblies composed of coding and non-coding RNAs, RNA-binding proteins, enzymes, and other proteins. Functionally, they are hubs for RNA storage, transport, signaling, and regulation of translation. A growing body of evidence now underscores their critical role in orchestrating processes within brain development. These granules facilitate neurodevelopment through the spatiotemporal regulation of gene expression; ensuring proteins are synthesized in the right place and time. For instance, the initial division and differentiation of neural precursor cells rely on mechanisms like transcriptional priming, a process facilitated by specific granules – processing bodies. As brain cells mature, RNA-protein granules enable the transport of transcripts to distant cellular sites. There, they regulate local protein synthesis, which is fundamental for cellular morphology, the maturation of dendritic spines, synaptic plasticity, and overall neural circuit connectivity. Furthermore, stress granules, which form transiently in response to cellular stress, are increasingly recognized as players in the developing central nervous system. It is hypothesized that stress granules promote cell survival during stressful events often accompanying embryonic development. Importantly, mutations in genes encoding RNA-protein granule proteins are associated with an increased risk for neurodevelopmental disorders. These mutations disrupt the dynamic nature of RNA-protein granules, leading to disturbances in mRNA localization and expression. Neurodevelopmental disorders linked to these mutations are often characterized by intellectual disability, speech delay, epileptic seizures, and autism spectrum disorder. The review summarizes the current data on the role of these RNA-protein granules – with a focus on stress granules, processing bodies, and transport granules – in shaping brain development.

Due to a sharp decline in numbers, the Yellow-breasted Bunting (Emberiza aureola) is listed as a threatened species on the IUCN Red List. Formerly an abundant inhabitant of meadows, it disappeared as a breeding species in Central Siberia in a short period between 1999 and 2006. We studied breeding density, habitat use, spatial structure and population dynamics of the Yellow-breasted Bunting population in the Yenisei middle taiga since 1978 in the years preceding the decline, and further on. The species showed a narrow specialization in the choice of habitats and occupied rare isolated patches of open habitats in taiga. Most breeding habitats were regularly populated at high densities, reached saturation and indicated a prosperous state of the population. Annual deviations in population size were small and were determined by wintering conditions. Regulation of numbers occurred at breeding sites through strict territorial relationships depending on density. In accordance with the model of ideal despotic distribution, excess individuals in years of increased abundance were displaced to habitats that were unsuitable for reproduction. This distribution was achieved independently in each isolated group of suitable habitats, and the exchange of individuals between groups was minimal. The noted population characteristics, together with the distinctive features of the subspecies E. a. aureola, suggest a long-term dependence of the ecology and dynamics of Yellow-breasted Bunting on the history of rice cultivation in Southeast Asia. The use of anthropogenic food resources in winter was likely reason for both previous expansion and modern decline in numbers due to changes in agricultural technologies. The millennial use of additional winter resources changed the parameters of the species’ life history in the direction of “slow life,” which did not contribute to the formation of adaptations to the conditions of the expanded range in the taiga zone. The current decrease in the availability of winter food has devalued the acquired changes and led to the collapse of the population. The extermination of birds in wintering grounds significantly accelerated the decline in numbers, but was hardly its main cause.