Heidari, S. | bioRxiv Science

bioRxiv2025

The Brain/MINDS 3D Digital Marmoset Brain Atlas Version 2.0: Population-based Cortical Region Parcellations with Multi-Modal Standard Templates

We present our new Brain/MINDS 3D digital marmoset brain atlas version 2.0 (BMA2.0), a population-based 3D digital brain atlas of the common marmoset (Callithrix jacchus), designed to overcome the limitations of previous single subject atlases that are prone to structural biases arising from individual variation. Here, manually delineated cortical regions from 10 myelin-stained brains were used to create a generalized cortical parcellation. Newly refined subcortical regions from a previous atlas and a completely new cerebellum parcellation were also incorporated, resulting in a comprehensive whole brain parcellation for both hemispheres. To facilitate multimodal data analysis, the atlas package includes co-registered average templates for myelin and Nissl staining from the same individuals, ex vivo MRI T2 (91 individuals), and in vivo MRI T2 (446 individuals). Cortical flat maps and pial, cortical mid-thickness, and white matter surfaces are also provided. BMA2.0 provides a central brain space for multimodal data integration, spatial analysis, and comparative neuroscience. Standard formats and transformations are provided for easy integration into existing workflows and interoperability with existing atlases.

neuroscience↗

bioRxiv2025

The molecular basis of sodium-dependent fluoride export by the eukaryotic fluoride channel FEX

Much of life on Earth, including plants, fungi, and bacteria, evolved to resist toxic environmental fluoride. In eukaryotes, the major resistance mechanism is fluoride export by FEX proteins. Using electrophysiology and transport assays, we establish that FEX from plants and yeasts are fluoride channels whose activity depends on reversible sodium ion binding. A cryo-EM structure of FEX from Candida albicans, together with mutagenesis studies, reveals a fluoride permeation route through a single phenylalanine-lined pore. Molecular dynamics simulations demonstrate that a cation binding motif adjacent to the pore provides a stable sodium binding site that is accessible from the external aqueous solution. We propose that sodium gating resolves a major conundrum of channel-based fluoride efflux by preventing fluoride permeation under conditions of membrane depolarization. Comparison to bacterial fluoride channels (Flucs) provides a unique glimpse of the evolution of structural and mechanistic complexity in a membrane protein family with inverted repeat architecture.

biophysics↗