Fear conditioning is widely used to assess associative memory in mice, yet percent freezing conflates memory with baseline locomotor and anxiety-related traits. A systematic survey of recent studies (2020–2025) found that fewer than 1% statistically integrate locomotor activity into freezing analyses. Here, we address this gap using a large-scale dataset of >10,000 mice across >160 comparisons, including genetic mutations, pharmacological interventions and aging, tested in 15 standardized behavioral paradigms. Conventional freezing scores covaried strongly with general locomotor activity, obscuring memory-related phenotypes. Multiple factor analysis identified two principal behavioral dimensions, locomotor activity and learning/memory: conventional freezing aligned with the locomotor dimension, whereas freezing subtraction and the activity suppression ratio mapped onto the memory dimension and improved detection of synaptic plasticity phenotypes. These analyses show that baseline locomotor normalization is essential for interpreting fear conditioning as a memory assay and provide an open framework for selecting and reporting locomotor-normalized metrics.
Daiki X. Sato, M. M. Chatzigiannis, Hirotaka Shoji et al.· bioRxiv· 0 citations
Abstract Ribosomal protein L41 (RPL41 or eL41) is the smallest ribosomal protein and forms the eukaryote-specific bridge, eB14, near the decoding center; however, its role in mammalian translation remains unclear. In this study, we established RPL41-deficient models of human HEK293T cells and mice to define its function. Cryo-electron microscopy revealed that RPL41 constrains intersubunit conformational dynamics without inducing major local static rearrangements. Loss of RPL41 altered A-site dynamics, slowed elongation, modestly increased amino acid misincorporation, and modestly enhanced readthrough of collision-inducing reporter sequences. Quantitative proteomic analysis suggested that these translational defects compromise long-protein homeostasis, as evidenced by increased insolubility and reduced abundance of long proteins. In vivo, Rpl41−/− mice were viable but exhibited growth retardation and decreased abundance of long proteins in tissues. Our findings reveal a conserved role for RPL41 in maintaining ribosome dynamics and translational fidelity, indicating that RPL41 supports ribosome function and long-protein homeostasis in mammals.
Mina Hirata, Maho Fujino, Kazuya Ichihara et al.· Nucleic Acids Research· 0 citations
