New tools for the analysis of glial cell biology in Drosophila

Abstract

Because of its genetic, molecular, and behavioral tractability, Drosophila has emerged as a powerful model system for studying molecular and cellular mechanisms underlying the development and function of nervous systems. The Drosophila nervous system has fewer neurons and exhibits a lower glia:neuron ratio than is seen in vertebrate nervous systems. Despite the simplicity of the Drosophila nervous system, glial organization in flies is as sophisticated as it is in vertebrates. Furthermore, fly glial cells play vital roles in neural development and behavior. In addition, powerful genetic tools are continuously being created to explore cell function in vivo. In taking advantage of these features, the fly nervous system serves as an excellent model system to study general aspects of glial cell development and function in vivo. In this article, we review and discuss advanced genetic tools that are potentially useful for understanding glial cell biology in Drosophila.

Fig. 1

GAL4 lines label specific subtypes of glial cells in adult fly brain. Adult cortex glia (A), ensheathing glia (B), and astrocyte-like glia (C) labeled with glial subtype-specific GAL4 lines driving expression of GFP (A) and mCD8::GFP (B and C). Entire subtype glial organization (A–C) and single cell of each subtype glia labeled by UAS-FLP-out (D–F) are shown. NP2222 (A and D), NP6520 (B and E), and NP1243 (C and F) were used for GAL4 drivers.

Fig. 2

Glial cells and neuronal subset can be independently labeled with two binary systems. Glial cells labeled with repo-LexA::GAD driven rCD2::GFP (Green) (A and D). Mushroom body neurons labeled with 247-GAL4 driven mCD8::RFP (B) and olfactory projection neurons labeled with GH146-GAL4 driven mCD8::RFP (C). Merged images are shown in [C] and [F].

Fig. 3

Glial cells labeled with twin-spot MARCM. Twin-spot clones of larval astrocyte-like glia in the neuropile (A) and larval subperineurial glia on the brain surface (B). Note in [B], two green and two magenta (one is shown by arrow with a broken line) subperinurial glial cells were labeled in cluster.