Rhodopsin gene expression determines rod outer segment size and rod cell resistance to a dominant-negative neurodegeneration mutant

PLoS One. 2012;7(11):e49889. doi: 10.1371/journal.pone.0049889. Epub 2012 Nov 21.


Two outstanding unknowns in the biology of photoreceptors are the molecular determinants of cell size, which is remarkably uniform among mammalian species, and the mechanisms of rod cell death associated with inherited neurodegenerative blinding diseases such as retinitis pigmentosa. We have addressed both questions by performing an in vivo titration with rhodopsin gene copies in genetically engineered mice that express only normal rhodopsin or an autosomal dominant allele, encoding rhodopsin with a disease-causing P23H substitution. The results reveal that the volume of the rod outer segment is proportional to rhodopsin gene expression; that P23H-rhodopsin, the most common rhodopsin gene disease allele, causes cell death via a dominant-negative mechanism; and that long term survival of rod cells carrying P23H-rhodopsin can be achieved by increasing the levels of wild type rhodopsin. These results point to promising directions in gene therapy for autosomal dominant neurodegenerative diseases caused by dominant-negative mutations.

Publication types

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

MeSH terms

  • Alleles
  • Animals
  • Gene Expression*
  • Genes, Dominant
  • Genetic Therapy
  • Mice
  • Mutation
  • Nerve Degeneration / genetics
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / physiopathology
  • Retinal Rod Photoreceptor Cells* / metabolism
  • Retinal Rod Photoreceptor Cells* / physiology
  • Retinitis Pigmentosa / genetics
  • Retinitis Pigmentosa / physiopathology
  • Rhodopsin / genetics*
  • Rhodopsin / metabolism
  • Rod Cell Outer Segment* / metabolism
  • Rod Cell Outer Segment* / physiology


  • Rhodopsin