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The VMD2 mutation R141H, which is associated with Best disease and other macular dystrophies, causes decreased Cl − channel activity
Author(s) -
Millar Ian D,
Burgess Rosemary,
Manson Forbes DC,
Black Graeme C,
Brown Peter D
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a541-a
Subject(s) - transfection , mutation , retina , mutant , biology , microbiology and biotechnology , gene , genetics , neuroscience
Best disease causes macular visual loss in early adulthood and is associated with autosomal dominant mutations in the VMD2 gene. VMD2 is expressed in the retinal pigment epithelium. Classical Best disease‐causing mutations lead to loss of Ca 2+ ‐actiavted Cl − channel activity in VMD2. We have studied the Cl − channel activity of a VMD2 mutant that is associated with Best disease and other macular dystrophies. HEK293 cells were transiently transfected with either WT VMD2 or R141H mutant VMD2 DNA. Cl − channel activity was measured using whole cell patch clamp. The bath was high NaCl Ringer and the pipette was low Cl − /high aspartate. Intracellular Ca 2+ was 500nM. Cells transfected with WT VMD2 exhibited large Cl − conductance with a reversal potential of −18.6±1.6mV (E Cl =−35mV). R141H VMD2 transfected cells also exhibited Cl − selective conductance (V rev =−15.6±3.0mV), but it was significantly reduced compared to WT (p<0.05). Cotransfection of cells with WT and R141H VMD2 gave Cl − selective conductance that was not significantly reduced compared to WT. These data further confirm that VMD2 functions as a Cl − ‐selective channel and that the R141H mutation is associated with reduced channel function. This work was supported by The Wellcome Trust.