Disease relevance of Crx

• METHODS: Crx and Otx2 were transferred into adult rat ciliary- and embryonic mesencephalon-derived neurospheres and adult rat iris-derived cells with the aid of a recombinant retrovirus [1].

High impact information on Crx

• In addition, the Crx gene transfer induced the specific antigens for rod photoreceptors in the iris-derived cells, which was not seen in the adult hippocampus-derived neural stem cells [2].
• These data suggest that Crx may play a crucial role in regulating pineal gene expression through interactions with PIRE [3].
• RESULTS: Pax6 expression occurred in all proliferating retinal neuroblasts in vivo; however, after their last mitotic division, photoreceptors stopped expressing Pax6 and started expressing Crx [4].
• Most postmitotic photoreceptors expressing Crx showed little axon development and few of them expressed opsin [4].
• In vitro, photoreceptor progenitors also showed a switch from Pax6 to Crx expression immediately after they exited the cell cycle and started differentiation [4].

Biological context of Crx

• The primary structure of the cone-rod homeobox protein (CRX), a member of the OTX-like homeobox protein family, in the rat was deduced from the cDNA nucleotide sequence [5].
• The purpose of this study was to determine whether Crx and Otx2--homeobox genes related to photoreceptor development--can induce the generation of these phenotypes in cells derived from adult ciliary and iris tissue and in mesencephalon-derived neural stem cells [1].
• Previous studies have shown that this effect of Crx is correlated with its ability to transactivate several genes of the phototransduction cascade [6].
• Transactivation was observed even with a portion of promoter carrying only one Crx-binding site and it was abolished by a mutation in this cis-regulatory element [6].
• In transient transfection experiments, Crx transactivated transcription of a reporter gene from the chicken HIOMT promoter [6].

Associations of Crx with chemical compounds

• Docosahexaenoic acid promotes photoreceptor differentiation without altering Crx expression [4].
• Here, we show that Crx can also act on the gene encoding the melatonin-synthesizing enzyme, hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4) [6].

Other interactions of Crx

• CONCLUSIONS: Crx and Otx2 effectively induced the generation of photoreceptor-specific phenotypes from ciliary- and iris-derived cells [1].
• At least two additional key components of the phototransduction cascade, recoverin and Gdeltat1, were expressed by Crx- and Otx2-transfected iris-derived cells [1].
• In primates, a combination of Crx and NeuroD was needed to induce monkey iris-derived cells to adopt photoreceptor-specific phenotypes [7].

Analytical, diagnostic and therapeutic context of Crx

• Northern blot analysis showed that Crx mRNA levels in the rat retina were constant under a daily light-dark cycle [5].
• Molecular cloning of the cone-rod homeobox gene (Crx) from the rat and its temporal expression pattern in the retina under a daily light-dark cycle [5].
• That both Crx and Otx2 induced phenotype generation in cells derived from iris or ciliary tissue may suggest an approach to photoreceptor cell preparation for retinal transplantation [1].

References