Date of Award

Spring 2022

Thesis Type

Rollins Access Only

Degree Name

Honors Bachelor of Arts

Department

Microbiology, Molecular Biology and Biochemistry

Sponsor

Dr. Jay Pieczynski

Committee Member

Dr. James Patrone

Committee Member

Dr. Kasandra Riley, Dr. Shan-Estelle Brown

Abstract

Kinesins, such as KLP-4, are critical motor proteins that traffic cargo across the neuron and are required for the proper functioning and regulation of neuronal signaling. By using Caenorhabditis elegans as a model organism, the structure, function, and characteristics of KLP- 4 can be better understood. Transgenesis and CRISPR-Cas9 technology were performed by injecting the ovaries of C. elegans with guide RNAs, homology-directed repair templates, and a co-injection marker to create serial truncations within the klp-4 gene and select for eGFP positive progeny. These serial truncations are used to determine how the absence of certain domains impact its function and ability to perform autoinhibition. It is hypothesized that the klp-4 (ok3537) within strain RB2546 is constitutively active as an in-frame deletion within the cargo-binding domain prevents autoinhibition from occurring. Transgenesis, followed by homologous end joining, resulted in frameshift mutations and the creation of klp-4 knockouts. These mutated progenies have significantly higher aldicarb sensitivity compared to EG9615 and a significantly lower aldicarb sensitivity compared to RB2546, determined through an aldicarb-induced paralysis assay. This moderate aldicarb sensitivity indicates that these mutants have a semi-rescued phenotype compared to RB2546, suggesting that the hypothesis is correct. Further experimentation is needed to verify these results, identify additional phenotypes, and determine the function and locomotion of truncated KLP-4 compared to the wild-type within the DA9 motor neuron. Determining how each domain of klp-4 influences the function of this kinesin will help improve the understanding of the homologous human kinesins that are responsible for causing neurodegenerative diseases.

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