Abstract
Purpose: :
The mechanisms that regulate the complex physiologic task of photoreceptor outer segment assembly remain an enigma. One limiting factor in revealing the mechanism(s) by which this process is modulated is that not all of the role players that participate in this process are known.
Methods: :
To determine some of the retinal proteins that likely play a critical role in regulating photoreceptor outer segment assembly we analyzed and compared the proteome map of tadpole Xenopus laevis retinal pigment epithelium (RPE)-supported retinas containing organized outer segments with that of RPE-deprived retinas containing disorganized outer segments. Solubilized proteins were labeled with CyDye fluors followed by multiplexed two-dimensional (2D) separation. The intensity of protein spots and comparison of proteome maps was performed using DeCyder software. Identification of differentially regulated proteins was determined using nanoLC-ESI-MS/MS analysis.
Results: :
We found a total of 27 protein spots, 21 of which were unique proteins, that were differentially expressed in retinas with disorganized outer segments. Only one of those proteins was a structural protein. The remaining proteins function in the regulation of cell development, cell signaling and the regulation of cell growth and proliferation. Interestingly, of those proteins known to be expressed in the eye, Müller glial cells, rather than photoreceptors, expressed the majority of the proteins.
Conclusions: :
In this study we have used identification and bioinformatics assessment of proteins that are differentially expressed in retinas with disorganized outer segments as a first step in determining probable key molecules involved in regulating photoreceptor outer segment assembly.
Keywords: photoreceptors • Muller cells • cell-cell communication