Msx1-Positive Progenitors in the Retinal Ciliary Margin Give Rise to Both Neural and Non-neural Progenies in Mammals

Publication date: Available online 20 December 2016
Source:Developmental Cell
Author(s): Marie-Claude Bélanger, Benoit Robert, Michel Cayouette
In lower vertebrates, stem/progenitor cells located in a peripheral domain of the retina, called the ciliary margin zone (CMZ), cooperate with retinal domain progenitors to build the mature neural retina. In mammals, it is believed that the CMZ lacks neurogenic potential and that the retina develops from one pool of multipotent retinal progenitor cells (RPCs). Here we identify a population of Msx1-expressing progenitors in the mouse CMZ that is both molecularly and functionally distinct from RPCs. Using genetic lineage tracing, we report that Msx1 progenitors have unique developmental properties compared with RPCs. Msx1 lineages contain both neural retina and non-neural ciliary epithelial progenies and overall generate fewer photoreceptors than classical RPC lineages. Furthermore, we show that the endocytic adaptor protein Numb regulates the balance between neural and non-neural fates in Msx1 progenitors. These results uncover a population of CMZ progenitors, distinct from classical RPCs, that also contributes to mammalian retinogenesis.

Graphical abstract

Teaser

The mammalian retina was thought to develop from a single pool of multipotent retinal progenitor cells (RPCs), but Bélanger et al. now identify a distinct progenitor population in the mouse retinal periphery that also contributes to retinogenesis in addition to producing non-neural ciliary epithelium.


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