Event Title

No Bones About It – Inhibition of Ocular Skeleton Formation by the Glutamine Analog DON

Faculty Advisor

Tyler Schwend

Graduation Year

2023

Location

Center for Natural Sciences

Start Date

4-4-2020 2:00 PM

End Date

4-4-2020 3:00 PM

Description

The eyes of many vertebrates, including birds, contain a concentric ring of 14-16 intramembranous bones (ossicles) organized within the scleral tissues that surround the cornea. Ossicles form upon the reception by scleral cells of a bone inducing signal(s) that emanates from neighboring papillae, which arise temporarily in the overlying conjunctiva. To date, little is known concerning how papillae development and how they induce ossicle formation. To further understand these mechanisms, we exposed developing bird (chicken) embryos to the glutamine analog, 6-Diazo-5-oxo-L-norleucine (DON). In the 1950s, DON was shown to inhibit ossicle formation. Now, 70 years later we are setting out to explore the mechanistic basis of this result. Herein, we confirm that high concentrations of DON inhibits ossicle formation, likely due to the absence of papillae. Lower concentrations of DON lead to varied numbers of disorganized papillae and misshapen ossicles. Gene expression analysis is underway to determine which genes are lacking in DON eyes that may prove necessary for papillae formation. Moreover, papillae transplantation experiments are being carried out to determine whether scleral tissue remains capable of forming bone in DON-treated eyes. Collectively, our use of DON-treated chicks will increase our understanding of papillae and ossicles in the developing eye.

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Apr 4th, 2:00 PM Apr 4th, 3:00 PM

No Bones About It – Inhibition of Ocular Skeleton Formation by the Glutamine Analog DON

Center for Natural Sciences

The eyes of many vertebrates, including birds, contain a concentric ring of 14-16 intramembranous bones (ossicles) organized within the scleral tissues that surround the cornea. Ossicles form upon the reception by scleral cells of a bone inducing signal(s) that emanates from neighboring papillae, which arise temporarily in the overlying conjunctiva. To date, little is known concerning how papillae development and how they induce ossicle formation. To further understand these mechanisms, we exposed developing bird (chicken) embryos to the glutamine analog, 6-Diazo-5-oxo-L-norleucine (DON). In the 1950s, DON was shown to inhibit ossicle formation. Now, 70 years later we are setting out to explore the mechanistic basis of this result. Herein, we confirm that high concentrations of DON inhibits ossicle formation, likely due to the absence of papillae. Lower concentrations of DON lead to varied numbers of disorganized papillae and misshapen ossicles. Gene expression analysis is underway to determine which genes are lacking in DON eyes that may prove necessary for papillae formation. Moreover, papillae transplantation experiments are being carried out to determine whether scleral tissue remains capable of forming bone in DON-treated eyes. Collectively, our use of DON-treated chicks will increase our understanding of papillae and ossicles in the developing eye.