Biology subjects

Eisman, R. C.

Publications and source records attributed to Eisman, R. C..

2 recordsLinked to original sources

bioRxiv2025

Adipocyte-Derived Amino Acid Storage Proteins are Required for Germline Stem Cell Maintenance in Adult Drosophila Females

Tissue homeostasis is dependent on precise coordination between endocrine organs in response to changes in organism physiology. Secreted circulating factors from adipocytes regulate the behavior of stem cell lineages in peripheral tissues in multiple organisms. In addition to their endocrine roles, Drosophila adipocytes store and secrete amino acid storage proteins throughout development. During the larval feeding period, adipocytes secrete storage proteins into the hemolymph, which are reabsorbed by the adipose tissue during metamorphosis to control adult organ size and fertility. Despite the known functions for storage proteins during the larval stages, their requirement during Drosophila adulthood and reproduction are uncharacterized. We discover that adipocyte-specific knockdown of the storage proteins Larval serum protein 1 (Lsp1) /{beta}/{psi} and Larval serum protein 2 (Lsp2) results in a decrease in GSC maintenance. We further reveal that decreased GSC number is due to downregulation of Target of Rapamycin (TOR) signaling in GSCs, suggesting compromised amino acid sensing directly in GSCs. We also find that the proteins that mediate storage protein adipocyte reabsorption, Fat body protein 1 (Fbp1) and Fat body protein 2 (Fbp2), are expressed in ovarian follicle cells. Intriguingly, Fbp1 nor Fbp2 appear to be required in follicle cells for GSC maintenance, suggesting undiscovered requirements for amino acid storage proteins in oogenesis. Our results highlight a novel role for Drosophila amino acid storage proteins during adulthood and in regulating tissue stem cell lineages.

developmental biology↗

bioRxiv2023

Auxin Exposure Disrupts Feeding Behavior and Fatty Acid Metabolism in Adult Drosophila

The ease of genetic manipulation in Drosophila melanogaster using the Gal4/UAS system has been beneficial in addressing key biological questions. Current modifications of this methodology to temporally induce transgene expression require temperature changes or exposure to exogenous compounds, both of which have been shown to have detrimental effects on physiological processes. The recently described auxin-inducible gene expression system (AGES) utilizes the plant hormone auxin to induce transgene expression and is proposed to be the least toxic compound for genetic manipulation, with no obvious effects on Drosophila development and survival in one wild-type strain. Here we show that auxin delays larval development in another widely-used fly strain, and that short- and long-term auxin exposure in adult Drosophila induces observable changes in physiology and feeding behavior. We further reveal a dosage response to adult survival upon auxin exposure, and that the recommended auxin concentration for AGES alters feeding activity. Furthermore, auxin fed male and female flies exhibit a significant decrease in triglyceride levels and display altered transcription of fatty acid metabolism genes. Although fatty acid metabolism is disrupted, auxin does not significantly impact adult female fecundity or progeny survival, suggesting AGES may be an ideal methodology for studying limited biological processes. These results emphasize that experiments using temporal binary systems must be carefully designed and controlled to avoid confounding effects and misinterpretation of results.

physiology↗