Genome wide array analysis indicates that an amyotrophic lateral sclerosis mutation of FUS causes an early increase of CAMK2N2 in vitro

Biochim Biophys Acta. 2013 Aug;1832(8):1129-35. doi: 10.1016/j.bbadis.2013.03.015. Epub 2013 Mar 29.

Abstract

Mutations in the RNA binding protein FUS (fused in sarcoma) have been linked to a subset of familial amyotrophic lateral sclerosis (ALS) cases. The mutations are clustered in the C-terminal nuclear localization sequence (NLS). Various FUS mutants accumulate in the cytoplasm whereas wild-type (WT) FUS is mainly nuclear. Here we investigate the effect of one ALS causing mutant (FUS-ΔNLS, also known as R495X) on pre-mRNA splicing and RNA expression using genome wide exon-junction arrays. Using a non-neuronal stable cell line with inducible FUS expression, we detected early changes in RNA composition. In particular, mutant FUS-ΔNLS increased calcium/calmodulin-dependent protein kinase II inhibitor 2 (CAMK2N2) at both mRNA and protein levels, whereas WT-FUS had no effect. Chromatin immunoprecipitation experiments showed that FUS-ΔNLS accumulated at the CAMK2N2 promoter region, whereas promoter occupation by WT-FUS remained constant. Given the loss of FUS-ΔNLS in the nucleus through the mutation-induced translocation, this increase of promoter occupancy is surprising. It indicates that, despite the obvious cytoplasmic accumulation, FUS-ΔNLS can act through a nuclear gain of function mechanism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / enzymology
  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / metabolism
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / biosynthesis
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / genetics*
  • Cell Line
  • Cell Nucleus / genetics
  • Chromatin / genetics
  • Chromatin / metabolism
  • Cytoplasm / genetics
  • Exons
  • Genome-Wide Association Study / methods
  • HEK293 Cells
  • Humans
  • Mutation*
  • Promoter Regions, Genetic
  • RNA Precursors / genetics
  • RNA Splicing / genetics
  • RNA-Binding Protein FUS / biosynthesis
  • RNA-Binding Protein FUS / genetics*

Substances

  • Chromatin
  • RNA Precursors
  • RNA-Binding Protein FUS
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2