Open AccessAn Inducible Expression System to Measure Rhodopsin Transport in Transgenic Xenopus Rod Outer Segments
Author(s) -
Xinming Zhuo,
Mohammad Haeri,
Eduardo Solessio,
Barry E. Knox
Publication year - 2013
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0082629
Subject(s) - mcherry , xenopus , rhodopsin , transgene , biology , biophysics , microbiology and biotechnology , green fluorescent protein , gene , biochemistry , retinal
We developed an inducible transgene expression system in Xenopus rod photoreceptors. Using a transgene containing mCherry fused to the carboxyl terminus of rhodopsin (Rho-mCherry), we characterized the displacement of rhodopsin (Rho) from the base to the tip of rod outer segment (OS) membranes. Quantitative confocal imaging of live rods showed very tight regulation of Rho-mCherry expression, with undetectable expression in the absence of dexamethasone (Dex) and an average of 16.5 µM of Rho-mCherry peak concentration after induction for several days (equivalent to >150-fold increase). Using repetitive inductions, we found the axial rate of disk displacement to be 1.0 µm/day for tadpoles at 20 °C in a 12 h dark /12 h light lighting cycle. The average distance to peak following Dex addition was 3.2 µm, which is equivalent to ~3 days. Rods treated for longer times showed more variable expression patterns, with most showing a reduction in Rho-mCherry concentration after 3 days. Using a simple model, we find that stochastic variation in transgene expression can account for the shape of the induction response.