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A De Novo Sequence Variant in Barrier-to-Autointegration Factor Is Associated with Dominant Motor Neuronopathy
Journal article   Open access   Peer reviewed

A De Novo Sequence Variant in Barrier-to-Autointegration Factor Is Associated with Dominant Motor Neuronopathy

Agathe Marcelot, Felipe Rodriguez-Tirado, Philippe Cuniasse, Mei-Ling Joiner, Simona Miron, Alexey A Soshnev, Mimi Fang, Miles A Pufall, Katherine D Mathews, Steven A Moore, …
Cells (Basel, Switzerland), Vol.12(6), 847
03/09/2023
DOI: 10.3390/cells12060847
PMCID: PMC10099716
PMID: 36980188
url
https://doi.org/10.3390/cells12060847View
Published (Version of record) Open Access

Abstract

Barrier-to-autointegration factor (BAF) is an essential component of the nuclear lamina. Encoded by , this DNA binding protein contributes to the regulation of gene expression, cell cycle progression, and nuclear integrity. A rare recessive BAF variant, Ala12Thr, causes the premature aging syndrome, Néstor-Guillermo progeria syndrome (NGPS). Here, we report the first dominant pathogenic BAF variant, Gly16Arg, identified in a patient presenting with progressive neuromuscular weakness. Although disease variants carry nearby amino acid substitutions, cellular and biochemical properties are distinct. In contrast to NGPS, Gly16Arg patient fibroblasts show modest changes in nuclear lamina structure and increases in repressive marks associated with heterochromatin. Structural studies reveal that the Gly16Arg substitution introduces a salt bridge between BAF monomers, reducing the conformation ensemble available to BAF. We show that this structural change increases the double-stranded DNA binding affinity of BAF Gly16Arg. Together, our findings suggest that BAF Gly16Arg has an increased chromatin occupancy that leads to epigenetic changes and impacts nuclear functions. These observations provide a new example of how a missense mutation can change a protein conformational equilibrium to cause a dominant disease and extend our understanding of mechanisms by which BAF function impacts human health.
Cell Nucleus - metabolism Chromatin DNA-Binding Proteins - metabolism Fibrinogen Humans Nuclear Proteins - metabolism

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