Juvenile Hormone Signaling Regulates Gene Expression in the Seminal Vesicle of Adult Male Drosophila melanogaster

Core Concepts

The seminal vesicle in adult male Drosophila melanogaster is a novel tissue that is responsive to juvenile hormone (JH) signaling, which induces the expression of the Lactate dehydrogenase (Ldh) gene.

Abstract

This study identifies the seminal vesicle as a JH-responsive tissue in adult male Drosophila melanogaster. The key findings are: The JH response element (JHRE)-GFP reporter is highly expressed in the epithelial cells of the seminal vesicle, indicating active JH signaling in this tissue. The JHRE-GFP signal in the seminal vesicle is increased upon administration of a JH analog and decreased when the JH receptors Methoprene-tolerant (Met) and Germ cell-expressed (Gce) are knocked down. The JHRE-GFP signal in the seminal vesicle is elevated after mating, consistent with the hypothesis that mating increases JH titer in male adults. The authors identified Lactate dehydrogenase (Ldh) as a JH-responsive gene that is highly expressed in the seminal vesicle epithelial cells. Ldh expression is regulated by Met and Gce, the intracellular JH receptors. The study suggests that JH signaling in the seminal vesicle may play a role in regulating the metabolism and function of this tissue, which is important for male reproduction.

Stats

The seminal vesicle epithelial cells show elevated JHRE-GFP signal upon JH analog administration. JHRE-GFP signal in the seminal vesicle is decreased when Met and gce are knocked down by RNAi. JHRE-GFP signal in the seminal vesicle is increased after mating. Ldh mRNA levels are upregulated in the seminal vesicle upon JH analog treatment. Ldh mRNA levels are decreased when Met and gce are knocked down in the seminal vesicle epithelial cells.

Quotes

"JHRE-GFP signal in the seminal vesicle epithelial cells was decreased by Met and gce double knockdown." "Ldh mRNA level was decreased by a double knockdown of Met and gce in the seminal vesicle epithelial cells."

Key Insights Distilled From

The seminal vesicle is a juvenile hormone-responsive tissue in adult male Drosophila melanogaster

by Kurogi,Y., M... at www.biorxiv.org 03-23-2024

https://www.biorxiv.org/content/10.1101/2024.03.20.585833v1

Deeper Inquiries

How does JH signaling in the seminal vesicle affect the quantity and/or quality of stored sperm?

Juvenile hormone (JH) signaling in the seminal vesicle can potentially impact the quantity and quality of stored sperm through various mechanisms. One way this can occur is by regulating the metabolic state of the seminal vesicle epithelial cells. In the study, it was found that Lactate dehydrogenase (Ldh), a JH-responsive gene expressed in the seminal vesicle, is involved in anaerobic metabolism. This suggests that JH signaling may influence the energy metabolism of the seminal vesicle, which could in turn affect the nourishment and maintenance of sperm stored in the tissue. Changes in metabolic activity can impact the availability of nutrients and energy sources for sperm, potentially influencing their quantity and quality. Additionally, JH signaling in the seminal vesicle may regulate the expression of other genes involved in sperm storage and maintenance. By influencing the expression of specific genes, JH can modulate various processes essential for sperm viability and function. For example, JH-responsive genes related to protein synthesis, transport, or storage could play a role in maintaining the structural integrity and functionality of stored sperm. Overall, JH signaling in the seminal vesicle likely plays a crucial role in maintaining the optimal environment for sperm storage, ensuring the viability and quality of stored sperm.

What other JH-responsive genes are expressed in the seminal vesicle, and how do they contribute to the tissue's function?

In addition to Lactate dehydrogenase (Ldh), other JH-responsive genes expressed in the seminal vesicle include Glutamate dehydrogenase (Gdh), CG10407, and CG10863. These genes were identified as highly enriched in the seminal vesicles and showed elevated expression levels in this tissue compared to the testes and male accessory glands. While the specific functions of these genes in the seminal vesicle are not fully elucidated, their expression patterns suggest potential roles in the tissue's function. Glutamate dehydrogenase (Gdh) is an enzyme involved in amino acid metabolism and energy production. Its presence in the seminal vesicle may indicate a role in nutrient metabolism and energy supply for the tissue or stored sperm. CG10407 and CG10863, whose functions are not well characterized, could potentially be involved in processes related to sperm storage, nourishment, or maintenance within the seminal vesicle. Overall, these JH-responsive genes likely contribute to the metabolic regulation, nutrient supply, and possibly other essential functions within the seminal vesicle, ensuring the proper environment for sperm storage and functionality.

Could the interplay between circadian clock factors and JH signaling in the seminal vesicle have broader implications for male reproductive physiology?

The interplay between circadian clock factors and JH signaling in the seminal vesicle could indeed have broader implications for male reproductive physiology. Circadian rhythms play a crucial role in coordinating various physiological processes, including metabolism, hormone regulation, and behavior. In the context of the seminal vesicle, where both circadian clock genes and JH-responsive genes are expressed, their interaction could influence the timing and coordination of reproductive activities. The coordination between circadian clock factors and JH signaling may regulate the timing of sperm production, storage, and release, aligning these processes with the optimal physiological conditions throughout the day. Disruption in this coordination could potentially impact male fertility and reproductive success. Additionally, the regulation of gene expression and metabolic activities by both circadian clock factors and JH signaling in the seminal vesicle could influence the overall health and functionality of the tissue, ultimately affecting male reproductive physiology. Understanding the crosstalk between circadian rhythms and JH signaling in the seminal vesicle may provide insights into the regulation of male reproductive processes, highlighting the importance of temporal coordination in maintaining reproductive fitness and success.