Octopamine receptor OAMB is required for ovulation in Drosophila melanogaster
Hyun-Gwan Lee1, Chang-Soo Seong, Young-Cho Kim
1Department of Biobehavioral Health and The Huck Institute of Life Sciences, 315 Health and Human Development East, Pennsylvania State University, University Park, PA 16802, USA.
Abstract:
Octopamine is a major monoamine in invertebrates and affects many physiological processes ranging from energy metabolism to complex behaviors. Octopamine binds to receptors located on various cell types and activates distinct signal transduction pathways to produce these diverse effects. We previously identified one of the Drosophila octopamine receptors named OAMB that produces increases in cAMP and intracellular Ca2+ upon ligand binding. It is expressed at high levels in the brain. To explore OAMB's physiological roles, we generated deletions in the OAMB locus. The resultant oamb mutants were viable without gross anatomical defects. The oamb females displayed normal courtship and copulation; however, they were impaired in ovulation with many mature eggs retained in their ovaries. RT-PCR, in situ hybridization, and expression of a reporter gene revealed that OAMB was also expressed in the thoracicoabdominal ganglion, the female reproductive system, and mature eggs in the ovary. Moreover, analysis of various alleles pinpointed the requirement for OAMB in the body, but not in the brain, for female fecundity. The novel expression pattern of OAMB and its genetic resource described in this study will help advance our understanding on how the neuromodulatory or endocrine system controls reproductive physiology and behavior.
Insights
The octopamine receptor OAMB is crucial for female fruit fly reproduction. OAMB mutations impair ovulation, retaining mature eggs, highlighting its role in reproductive physiology.
Area of Science:
- Neurobiology
- Reproductive Biology
- Invertebrate Physiology
Background:
- Octopamine is a key invertebrate monoamine influencing diverse physiological processes.
- Octopamine receptors mediate distinct signal transduction pathways.
- The Drosophila octopamine receptor OAMB increases cAMP and Ca2+ upon binding and is highly expressed in the brain.
Purpose of the Study:
- To investigate the physiological roles of the octopamine receptor OAMB.
- To characterize the function of OAMB in Drosophila melanogaster reproduction.
Main Methods:
- Generation of OAMB locus deletion mutants (oamb).
- Phenotypic analysis of oamb mutants, including courtship, copulation, and ovulation.
- Gene expression analysis using RT-PCR, in situ hybridization, and reporter gene expression.
- Allelic analysis to determine OAMB's functional localization.
Main Results:
- oamb mutants are viable with no gross anatomical defects.
- oamb females exhibit normal courtship and copulation but are impaired in ovulation, retaining mature eggs.
- OAMB expression was detected in the thoracicoabdominal ganglion, female reproductive system, and mature eggs.
- OAMB is required in the body, not the brain, for female fecundity.
Conclusions:
- OAMB plays a critical role in female reproductive physiology, specifically ovulation.
- The study reveals a novel expression pattern for OAMB in reproductive tissues.
- This research provides a valuable genetic resource for studying neuromodulatory control of reproduction.
