Abstract
Purpose: :
Lineage analyses of vertebrate retinas have established that rodent retinal progenitors are multipotent and extrinsic factors can influence the cell fate determination. Several extrinsic factors, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF) and oncostatin (OSM) were added to postnatal rat retina explants resulted in a dramatic reduction in opsin expression. A ubiquitously expressed signal transduction receptor component gp130 has been demonstrated to be shared by all these cytokine factors. The expression levels of these endogenous cytokines in dorsal and ventral retinas of a transgenic mouse line (h–GNAT2pro–DTA) that failed to develop rod and cone photoreceptors in the ventral retina are measured.
Methods: :
Total RNAs were prepared from transgenic dorsal and ventral retinas between postnatal day 0 (P0) and P8. The expression levels of the cytokines in these tissues between P0 and P8 were monitored every other day by RT–PCR. Same amounts of total RNAs were reverse transcribed, aliquots of single stranded cDNAs were used for PCR. Samples were taken at 20, 25 and 30 cycles and analyzed by argarose gel electrophoresis. To initiate the analysis, the expression of CNTF and gp130 in dorsal and ventral transgenic retinas is reported.
Results: :
The expression levels of CNTF and the shared receptor gp130 in transgenic ventral retina are equal or less than those in the corresponding dorsal retina between P0 and P10.
Conclusions: :
The failure to develop photoreceptors in the transgenic ventral retina is not due to the expression of the extrinsic factor CNTF or other related cytokines. Therefore, lacking of cone photoreceptors might effect the rod development in the h–GNAT2pro–DTA transgenic mouse.
Keywords: development • photoreceptors