The C175R mutation alters nuclear localization and transcriptional activity of the nephronophthisis NPHP7 gene product

Eur J Hum Genet. 2016 May;24(5):774-8. doi: 10.1038/ejhg.2015.199. Epub 2015 Sep 16.

Abstract

Nephronophthisis (NPH) is a rare autosomal ciliopathy, but the leading cause for hereditary end-stage renal disease in children. Most NPH family members form large protein networks, which appear to participate in structural elements of the cilium and/or function to restrict access of molecules to the ciliary compartment. The zinc-finger protein GLIS2/NPHP7 represents an exception as it has been implicated in transcriptional regulation; only two families with GLIS2/NPHP7 mutations and typical NPH manifestations have been identified so far. We describe here that the recently identified GLIS2/NPHP7(C175R) point mutation abolished the nuclear localization of GLIS2/NPHP7. Forced nuclear import did not rescue the transcriptional defects of GLIS2/NPHP7(C175R), indicating additional defects as DNA-binding protein. We further observed that wild type, but not GLIS2/NPHP7(C175R), prevented the cyst formation caused by depletion of nphp7 in zebrafish embryos. Taken together, our findings indicate that the C175R mutation affects both localization and function of GLIS2/NPHP7, supporting a role of this mutation in NPH, but questioning the direct involvement of GLIS2/NPHP7 in ciliary functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Cell Nucleus / metabolism*
  • HEK293 Cells
  • Humans
  • Kidney Diseases, Cystic / genetics*
  • Kruppel-Like Transcription Factors / genetics*
  • Kruppel-Like Transcription Factors / metabolism
  • Mutation, Missense*
  • Protein Binding
  • Transcriptional Activation
  • Zebrafish

Substances

  • GLIS2 protein, human
  • Kruppel-Like Transcription Factors

Supplementary concepts

  • Nephronophthisis 7