posted on 2016-02-20, 07:37authored byAndrew
R. Lee, Rachel R. Lamb, Julietta H. Chang, Petra Erdmann-Gilmore, Cheryl F. Lichti, Henry W. Rohrs, James P. Malone, Yogesh P. Wairkar, Aaron DiAntonio, R. Reid Townsend, Susan M. Culican
Retinal ganglion cells (RGCs) transmit visual information
topographically
from the eye to the brain, creating a map of visual space in retino-recipient
nuclei (retinotopy). This process is affected by retinal activity
and by activity-independent molecular cues. Phr1,
which encodes a presumed E3 ubiquitin ligase (PHR1), is required presynaptically
for proper placement of RGC axons in the lateral geniculate nucleus
and the superior colliculus, suggesting that increased levels of PHR1
target proteins may be instructive for retinotopic mapping of retinofugal
projections. To identify potential target proteins, we conducted a
proteomic analysis of optic nerve to identify differentially abundant
proteins in the presence or absence of Phr1 in RGCs.
1D gel electrophoresis identified a specific band in controls that
was absent in mutants. Targeted proteomic analysis of this band demonstrated
the presence of PHR1. Additionally, we conducted an unbiased proteomic
analysis that identified 30 proteins as being significantly different
between the two genotypes. One of these, heterogeneous nuclear ribonucleoprotein
M (hnRNP-M), regulates antero-posterior patterning in invertebrates
and can function as a cell surface adhesion receptor in vertebrates.
Thus, we have demonstrated that network analysis of quantitative proteomic
data is a useful approach for hypothesis generation and for identifying
biologically relevant targets in genetically altered biological models.