Date of Award

Fall 2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Cell Biology

First Advisor

Colón-Ramos, Daniel

Abstract

Animals must be able to flexibly deploy distinct behavioral strategies that allow them to fulfill specific goals in a shifting environment. I used the thermotaxis behavior of the nematode Caenorhabditis elegans as a paradigm to study the deployment and transition between two complementary behavioral strategies, gradient migration and isothermal tracking. I performed reverse and forward genetic screens to examine the contribution of known and novel molecules that regulate the execution of these two strategies. I found a novel allele of the gap junction gene inx-1/Innexin and demonstrated that it is required to terminate isotherm-oriented forward runs. Mutants for this gene abnormally perform isothermal tracking for longer periods and outside the range of temperatures normally deployed in wild-type worms. I demonstrated that inx-1/Innexin acts on a pair of interneurons called AIY which, in inx-1 mutants, display a hyperactive, asynchronous calcium activity between the AIY pair. This phenotype is especially strong during presentation of small magnitude temperature stimuli. Together, my findings uncover a novel role for an electrical synapse gene, inx-1, in regulating how temperature sensory stimulus is transduced into the controlling neuronal circuit, and how this dysregulation in cellular activity gives rise to a shift in the endogenous action selection program between the behavioral strategies of gradient migration and isothermal tracking.

Download

Share

COinS