Abstract
Purpose: :
Nuclear co-receptor (NCoR) is part of a multiprotein complex that exhibits histone deacetylase (HDAC) activity in vivo. Specifically, NCoR has been shown to repress transcription of retinoic acid receptors that are important for retinal development. The purpose of this study was to investigate NCoR expression in developing and adult mouse and human retinas as well as in mouse retinal progenitor cells.
Methods: :
Immunohistochemistry was used to analyze sections for expression of NCoR in the following tissues: 2 post-natal day 1 (P1) mouse eyes, 28 normal adult mouse eyes (P41-P347), 2 human fetal eyes, and 3 normal adult human eyes (donors aged 17, 53, and 90 years). Relative levels of NCoR expression were evaluated in undifferentiated and differentiated mouse retinal progenitor cells via PCR.
Results: :
P1 mouse retinas showed mild nuclear staining for NCoR although specific retinal layers are not evident at this stage. All adult mice had mild nuclear staining in the inner and outer nuclear layers of the retina except for the oldest mice (P347), which had no outer nuclear layer staining and cytoplasmic inner nuclear layer staining. All eyes except for one showed expression of NCoR in photoreceptor inner segments while cytoplasmic staining in ganglion cells was observed in the P347 and P41 eyes. Staining was predominantly nuclear in both human fetal retinas. Adult human eyes showed consistent mild expression in the photoreceptor layer and mild to strong staining in the outer plexiform layer. The youngest donor further showed nucelar expression in the inner and outer nuclear layers while the 53 year-old donor had cytoplasmic expression in the ganglion cell layer. PCR analysis demonstrated that NCoR was expressed at similar levels in undifferentiated and differentiated mouse retinal progenitor cells.
Conclusions: :
NCoR is expressed in mouse retinal progenitor cells as well as in developing human and mouse retinas, highlighting a putative role for this protein in retinal development. Further research is needed to determine whether or not the manipulation of NCoR expression during retinal development can favor the production of specific retinal cell subtypes. Additionally, the expression of NCoR in adult mouse and human retinas further suggests a possible role for this protein in normal retinal physiology. Future research will investigate the specific processes regulated by NCoR in the retina.
Keywords: retinal development • retina • development