Identification of GPCR-GAL4 lines expressed in the gastrointestinal track in the fruit fly

Abstract

The gut is the organ where digestion, absorption of nutrients, and excretion of waste take place. G-Protein Coupled Receptor (GPCR), the largest group of membrane receptors and major pharmaceutical drug targets, is involved in a plethora of physiological processes, including those associated with the gut. However, the physiological functions of GPCRs expressed in the gut remain largely unclear. As a first step toward uncludating the gut GPCR functions, I utilized a genetically amenable model organism, Drosophila melanogaster and examined expression patterns of GPCRs. There are a total of 117 GPCRs in Drosophila. In this thesis, I examined the gut expression of 86 GPCR using GAL4-UAS system. Among 86 GPCR-GAL4 lines, 61 were found expressed in the fruit fly gut. Cell types expressing GPCRs include enteric neurons (ENs), enterocytes (ECs), intestinal stem cells (ISCs), enteroblasts (EBs), enteroendocrine cells (EEs), and visceral muscle cells (VMs). ENs, ECs, ISCs, EBs, EEs and VMs expresses 41, 34, 7, 17, 27, 15 GPCRs, respectively. This study will guide future studies that aim to uncover functions of GPCRs expressed in the gut.