Astrocyte-like glia-specific gene deathstar is crucial for normal development, adult locomotion and lifespan of male Drosophila

Abstract

The brain of Drosophila melanogaster is a complex organ with various cell types, orchestrating the physiology and behaviors of the fly. While each cell type in the Drosophila brain is known to express a unique set of genes, their complete genetic profile is still unknown. Advances in the RNA-sequencing techniques at single cell resolution facilitate identifying novel cell type-specific markers and/or examining the specificity of the available markers. In this study, exploiting a single cell RNA sequencing data of Drosophila optic lobe (which comprises two thirds of the brain with extensive cell type diversity), we first categorized cell types based on their known molecular markers, then the genes with enriched expression in astrocytes were identified. Consistent with previous findings, the known glial markers CG34335, Inx2 and nrv2 as well as the astrocytic genes CG9394, Eaat1, Gat, Gs2 and CG1552 exhibited enriched expression in the identified astrocyte cluster. Moreover, we identified CG11000 as a gene with positive expression correlation with the astrocytic marker Eaat1. The positive expression correlation between CG11000 and Eaat1 genes was also observed in the single-cell RNA-sequencing data of Drosophila mid-brain as well as in the bulk RNA-sequencing data of Drosophila whole brain during development. Immunostaining of the brains dissected from adult flies showed overlapping fluorescence signals of CG11000 and Eaat1 expression, supporting co-expression of these genes in a set of single cells in Drosophila optic lobe. At the physiological level, RNAi-mediated suppression of CG11000 impeded th normal development of male flies without any effects on females. In adult flies, CG11000 suppression affected the locomotion activity and lifespan of D. melanogaster in an astrocyte-specific manner, suggesting pivotal role of CG11000 gene in astrocytes.