PAX6 is essential for eye and forebrain development but how PAX6 instructs retinal versus neuroectoderm specification remains unknown. We found that the paired-less PAX6, PAX6D, is uniquely expressed in retinal cells during human eye development and along human embryonic stem cell (hESC) differentiation to retinal cells. HESCs with deletion of PAX6D failed to enter retinal differentiation. Induced expression of PAX6D but not PAX6A under the PAX6-null background restored the retinal differentiation capacity. ChIP-Seq, confirmed by functional assays, revealed a set of retinal genes and neural genes that are targets of PAX6D, including WNT8B. Inhibition of WNTs restored the retinal differentiation capacity of neuroepithelia with PAX6D knockout whereas activation of WNTs blocks retinal differentiation even when PAX6D is induced. Thus, PAX6D specifies neuroepithelia to retinal cells, partly via regulation of WNTs. SOURCE: Su-chun Zhang University of Wisconsin - Madison

Pluto Bioinformatics

GSE128140: Gene expression in retinal cells from wildtype H9 human embryonic stem cells, PAX6 KO and PAX6D KO cell lines