Spatial regulation of NSUN2-mediated tRNA m5C installation in cognitive function.

Enzyme-mediated modifications of tRNA, such as 5-methylcytosine (m5C) installed by nuclear-enriched NOP2/Sun RNA methyltransferase 2 (NSUN2), play a critical role in neuronal development and function. However, our understanding of these modifications' spatial installation and biological functions remains incomplete. In this study, we demonstrate that a nucleoplasm-localized G679R NSUN2 mutant, linked to intellectual disability, diminishes NSUN2-mediated tRNA m5C in human cell lines and Drosophila.

An interphase actin wave promotes mitochondrial content mixing and organelle homeostasis.

Across the cell cycle, mitochondrial dynamics are regulated by a cycling wave of actin polymerization/depolymerization. In metaphase, this wave induces actin comet tails on mitochondria that propel these organelles to drive spatial mixing, resulting in their equitable inheritance by daughter cells. In contrast, during interphase the cycling actin wave promotes localized mitochondrial fission.