Canine cone transducin-gamma gene and cone degeneration in the cd dog

Invest Ophthalmol Vis Sci. 1998 Sep;39(10):1775-81.

Abstract

Purpose: To characterize the cDNA and the organization of the gene encoding the cone-specific gamma subunit of transducin (Tgamma c) and to examine this gene as a candidate for the recessively inherited cone photoreceptor degeneration in the cd dog.

Methods: Canine Tgamma c cDNA was cloned and sequenced. Polymerase chain reaction (PCR) was used to define the Tgamma c gene structure, northern blot analysis to examine the level of expression of Tgamma c mRNA in control and cd-affected retinas, and immunocytochemistry to determine the presence and localization of Tgamma c in normal and cd retinas.

Results: Immunocytochemical results showed Tgamma c localized to cone photoreceptor outer segments in the normal retina, whereas no Tgamma c immunoreactivity was observed in the cd retinas. However, the level of transcription and the primary structure of the cloned cDNA coding for the 69-amino acid protein were identical in retinas from wild-type and affected dogs.

Conclusions: Although Tgamma c immunoreactivity was specifically absent in the cd dog retina, no differences were detected between normal and cd retinas in the nucleotide sequence of Tgamma c mRNA or in its synthesis. These results indicate that a mutation in the Tgamma c gene may not be causally associated with the cd dog disease. These findings suggest that possible abnormalities in posttranslational modification of Tgamma c or defective assembly of the transducin alphabetagamma complex could lead to rapid degradation of Tgamma c.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Northern / veterinary
  • Cloning, Molecular
  • DNA, Complementary / analysis*
  • Dog Diseases / genetics*
  • Dog Diseases / metabolism
  • Dog Diseases / pathology
  • Dogs
  • Immunoenzyme Techniques / veterinary
  • Molecular Sequence Data
  • Polymerase Chain Reaction / veterinary
  • RNA / isolation & purification
  • RNA, Messenger / metabolism
  • Retinal Cone Photoreceptor Cells / metabolism*
  • Retinal Cone Photoreceptor Cells / pathology
  • Retinal Degeneration / genetics
  • Retinal Degeneration / metabolism
  • Retinal Degeneration / pathology
  • Retinal Degeneration / veterinary*
  • Sequence Analysis, DNA
  • Transducin / genetics*
  • Transducin / metabolism

Substances

  • DNA, Complementary
  • RNA, Messenger
  • RNA
  • Transducin

Associated data

  • GENBANK/AF038862