技术资料

Background and Objectives: Recent studies have identified variants in the kinesin family member 5A (KIF5A) gene that predispose to amyotrophic lateral sclerosis (ALS). These ALS-linked KIF5A variants lead to the exclusion of exon 27,resulting in the production of a mutated protein with an altered C-terminal region (KIF5A ΔExon27). Through whole genome sequencing,we identified a novel KIF5A intronic variant,rs1057522322 (c.2993-6C > A; chr12:57582596C > A,GRCh38.p14),in a family segregating ALS. Our goal is to investigate the effect of this variant on exon 27 splicing and to assess its functional consequences on KIF5A-mediated cargo transport. Methods: Induced pluripotent stem cells (iPSCs) were generated from siblings with and without the c.2993-6C > A variant. RT-PCR was performed on RNA extracted from iPSC-derived neurons to assess exon 27 splicing. Functional studies were conducted on iPSC-derived motor neurons (MNs). Results: RT-PCR confirmed that the c.2993-6C > A variant induced exon 27 skipping in KIF5A. Immunofluorescent staining showed that KIF5A ΔExon27 abolished the axonal interaction with splicing factor proline- and glutamine-rich,a cargo specifically transported by KIF5A. Under stress conditions,MNs carrying the c.2993-6C > A variant exhibited TDP-43 proteinopathy. Discussion: KIF5A intronic variant c.2993-6C > A could be a risk factor for ALS. KIF5A ΔExon27 impairs KIF5A-mediated cargo transport and contributes to ALS pathogenesis in a TDP-43–dependent manner. View Publication

Neural crest cells contribute to craniofacial formation by differentiating into skeletogenic mesenchyme and neuro-glial lineages. Using Smart-seq2 single-cell transcriptomics,we show that mesenchymal fate commitment correlates specifically with the expression of rRNA-modifying and ribosome assembly factors,rather than structural ribosomal proteins. Notably,EMG1 and NHP2 introduce key post-transcriptional modifications into 18S rRNA,including m¹acp³ψ at U1248,which requires TSR3 for final maturation. Disrupting NHP2 or TSR3 in vitro and in vivo perturbs cranial neural crest differentiation; post-migratory temporal knockout of Polr1a or Polr1c also causes craniofacial malformations. These findings align with cell type-specific m¹acp³ψ levels during neural crest differentiation. Given the neural crest contribution to neuroblastoma,we analyze patient data to find that elevated ribosomal control and rRNA-modifying proteins predict poorer outcomes. Complementary experiments in neuroblastoma cell lines reveal functional roles for TSR3 and WDR74 in mesenchymal-like tumor states. Together,our results link rRNA modifications and ribosome assembly to fate decisions,suggesting ribosomal heterogeneity shapes both normal development and tumor progression. Neural crest cells differentiate into skeletogenic mesenchyme and neuro-glial lineages,thereby contributing to craniofacial formation. Here,single-cell analysis of cranial neural crest shows that specific rRNA modification and ribosome assembly factors contribute to skeletogenic fate. Their disruption causes craniofacial defects,while high levels in neuroblastoma predict poor survival. View Publication