Distinct nuclear localization patterns of DNA methyltransferases in developing and mature XXXX retina.

@entity1 @entity19 @entity15786 @entity15894 @entity16610
DNA methyltransferases-- @entity16610 , @entity15786 , and @entity15894 --produce methylation patterns that dynamically regulate chromatin remodeling and gene expression. The vertebrate retina provides an ideal model to elucidate molecular control of neurogenesis as all neuronal cell types and M  ller glia are generated in a conserved order from common pools of progenitor cells. As a prelude to exploring epigenetic regulation of @entity1 retinal development, we investigated the expression of @entity16610 , @entity15786 , and @entity15894 in the @entity19 retina from embryonic day (E) 10.5 to 10 months of age. High levels of transcripts for all three Dnmt genes were observed in early stages of retinal differentiation, with significantly reduced expression after birth. Although @entity16610 protein is abundant in retinal progenitors at E10.5, it becomes restricted to postmitotic cells by E15.5. Most cells in the postnatal retina show nuclear immunostaining of @entity16610 ; however, the photoreceptors exhibit distinctive patterns. In rods, weak expression of @entity16610 is detected in perinuclear region and in the nucleus, whereas a strong nuclear labeling is evident in cones. @entity15786 and @entity15894 show a discrete pattern in developing retina with high expression at E11.5, little or no immunostaining by E15.5, and then postnatal expression overlapping with @entity16610 in early born neurons (ganglion, amacrine and horizontal cells, and cones). Robust nuclear localization of DNMTs in cones compared to rods suggests a potential role of DNA methylation in differential remodeling of chromatin in these two specialized neurons. Our studies indicate that DNA methyltransferases contribute to the establishment and maturation of cell fates during retinal development.
