The embryonic eye is composed of a number of ectoderm-derived structures that ultimately give rise to a diverse array of cell types and complex tissues. Extensive cell-cell communication and precisely coordinated molecular events are necessary to differentiate the associated cell types, including within the retina. Embryonic days 4 and 5 of chicken development encompass a critical window of ocular formation, during which the retinal pigment epithelium (RPE) becomes fate-restricted and several neural retina cell lineages emerge. However, many gaps remain in our understanding of the molecular events that underlie these changes. To address this lacuna, we performed single-nucleus RNA-seq on the chicken eye at days 4 and 5 of development, with the objective of uncovering marker genes for novel cell types that may direct retina development or determine regenerative competence. Following marker identification, we performed fluorescent in situ hybridization in order to spatially evaluate the uncovered cell types. Using this approach, we uncovered numerous genes associated with neurocompetent or fate-restricted RPE cell states, such as MEIS1/2, PAX6, OTX2, and cadherin-encoding genes. In addition, we identified several populations of mesenchyme cells in close proximity to the RPE that express TGFb family-encoding RNAs with the potential to influence RPE behavior. Finally, we assess gene expression patterns within the ciliary margin, and contrast these observations to the neurocompetent RPE. Altogether, we present a cell atlas that encompasses a critical window of chicken eye development. Broadly, the cellular and molecular dynamics uncovered, stand to broaden our understanding of how these cell types may participate in ocular development, regeneration, and pathology. This work was supported by NEI R01 EY026816 to KDRT, the Rapid Grant Program at Miami University (MU), NINDS F99 NS129167 to JAT, and the Department of Biology at MU.
Author(s): Sofia Rebull, Biology Major
Advisor(s): Katia Del Rio-Tsonis, Department of Biology
Jared Tangeman, Department of Biological Sciences
You must be logged in to post a comment.