The Effects of Glycolytic Mutations in Drosophila melanogaster Muscle Development

Author

Coco Lim, CUNY Bernard M Baruch CollegeFollow

Date of Award

Fall 5-1-2023

Document Type

Thesis

Degree Name

B.S.

Honors Designation

yes

Program of Study

Biology

Language

English

First Advisor

Krista C. Dobi

Second Advisor

Jean Gaffney

Third Advisor

Pablo Peixoto

Abstract

Muscle atrophy, or muscle wasting, is caused due to lack of physical activity for an extended period of time, due to muscle diseases (such as muscle dystrophies), cancer chemotherapies, and aging. It is also extensively found on astronauts after spaceflight, particularly missions of long durations. Muscle cells are dependent on different metabolic pathways to optimize Adenosine triphosphate (ATP) production to compensate for muscle exertion. Glycolysis converts glucose into ATP producing pyruvate, which can be sent into the citric acid cycle or converted to lactate (lactic acid). Muscles preferentially use lactate production, despite the fact that fewer molecules of ATP are generated, because it is a faster process. Glycolysis from glucose and stored glycogen is capable of generating ATP more efficiently compared to other metabolic pathways. However, there is still a gap in knowledge regarding the role of the glycolytic pathway in muscle function and wasting. This crucial process is highly conserved from fruit flies (Drosophila melanogaster) to humans. Through mutations of two fundamental glycolytic enzymes, phosphofructokinase (Pfk) and lactate dehydrogenase (Ldh), we are examining the effects of modulating glycolytic enzyme function on fruit flies’ muscle development and function. The knockdown of Pfk and Ldh function in muscle is expected to lead to defects in larval sarcomeres and flightless adult flies. We used GAL4/UAS to drive both overexpression and RNA interference against Pfk and Ldh. We examined the muscle morphology in embryos and larvae by immunohistochemistry and live imaging, using antibodies to myosin heavy chain (overall muscle structure) and alpha-actinin (sarcomere length), a nuclear dsRed transgene (nuclear number and positioning) and Zasp-GFP transgene (sarcomere structure). These experiments use fixed embryos and dissected larvae imaged with confocal microscopy to evaluate any changes in their muscle structure. Larval crawling showed a lack of effect on motor behavior of MHC-Gal4 tub-Gal80ts x UAS-Pfk and UAS-Pfk-RNAi. Confocal microscopy imaging showed a decrease in sarcomere length in loss-of-function Pfk larval ventrolateral muscles. Additionally, there were defects in ventrolateral muscles found in the downregulation of Pfk, suggesting a potential mechanism shift resulting in glucose 6-phosphate changing to other metabolic pathways.

Recommended Citation

Lim, Coco, "The Effects of Glycolytic Mutations in Drosophila melanogaster Muscle Development" (2023). CUNY Academic Works.
https://academicworks.cuny.edu/bb_etds/182