Comparison of the Effect of Stress Hormone Receptors on the Morphology ofXenopus tropicalis Tadpoles

Abstract

By Kala Mertz, Biology

Advisor: Daniel Buchholz

Presentation ID: PM_ATRIUM43

Abstract: All organisms experience various forms of stress. Stress during the early stages of life may have detrimental effects to fitness, health, growth, and development. Stress is mediated through stress hormones, mainly corticosterone (CORT) in frogs. The main developmental hormone that can induce almost all the changes observed during metamorphosis is the thyroid hormone (TH), however, some changes are unaccounted for which is where CORT may play a vital role. CORT can act through two different receptors, the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), which makes it difficult to study its impact on organisms. The goal of this study is to understand the influence of MR and GR on development. To answer this question, CRISPR (clustered regularly interspaced short palindromic repeats) gene disruption technology was utilized to produce both MR and GR knockout lines to study organisms lacking MR and GR.  This is necessary to be able to focus on only one of the two receptors.  Growth and development were measured comparing wild-type animals to the knockout animals. Development was recorded by using a set of previously established stages that look at physical characteristics of the tadpole.  Growth was measured using snout-vent length (SVL). A study previously performed in the lab showed that when compared to wild-type animals, GR knockouts develop at a faster rate until a certain stage and then their development stalls. It also showed that GR knockouts ultimately die before the completion of metamorphosis, while wild-type animals survive.