EXOSC8 mutations alter mRNA metabolism and cause hypomyelination with spinal muscular atrophy and cerebellar hypoplasia

Nat Commun. 2014 Jul 3:5:4287. doi: 10.1038/ncomms5287.

Abstract

The exosome is a multi-protein complex, required for the degradation of AU-rich element (ARE) containing messenger RNAs (mRNAs). EXOSC8 is an essential protein of the exosome core, as its depletion causes a severe growth defect in yeast. Here we show that homozygous missense mutations in EXOSC8 cause progressive and lethal neurological disease in 22 infants from three independent pedigrees. Affected individuals have cerebellar and corpus callosum hypoplasia, abnormal myelination of the central nervous system or spinal motor neuron disease. Experimental downregulation of EXOSC8 in human oligodendroglia cells and in zebrafish induce a specific increase in ARE mRNAs encoding myelin proteins, showing that the imbalanced supply of myelin proteins causes the disruption of myelin, and explaining the clinical presentation. These findings show the central role of the exosomal pathway in neurodegenerative disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agenesis of Corpus Callosum / genetics*
  • Amino Acid Sequence
  • Animals
  • Cerebellum / abnormalities*
  • Cerebellum / pathology
  • Cerebral Cortex / pathology
  • Developmental Disabilities / genetics
  • Developmental Disabilities / pathology
  • Exosome Multienzyme Ribonuclease Complex / genetics*
  • Female
  • Fungal Proteins / metabolism
  • Gene Expression
  • Gene Knockdown Techniques
  • Hereditary Central Nervous System Demyelinating Diseases / genetics*
  • Hereditary Central Nervous System Demyelinating Diseases / pathology
  • Homozygote
  • Humans
  • Infant
  • Male
  • Molecular Sequence Data
  • Nervous System Malformations / genetics*
  • Nervous System Malformations / pathology
  • RNA-Binding Proteins / genetics*
  • Sequence Analysis, DNA
  • Spinal Muscular Atrophies of Childhood / genetics*
  • Syndrome
  • Zebrafish

Substances

  • Fungal Proteins
  • RNA-Binding Proteins
  • EXOSC8 protein, human
  • Exosome Multienzyme Ribonuclease Complex

Supplementary concepts

  • Cerebellar Hypoplasia