Genetic analysis of gliogenesis in Drosophila

Abstract

Abstract Neural circuits are made up of interconnecting neurons, and processing of information can be explained purely on the basis of neuronal properties. However, in all complex nervous systems, non-neuronal cells—the glial cells—also have to be considered. During the evolution of metazoans, the number of glial cells increases in relation to the complexity of the nervous system. In the vertebrate central nervous system (CNS), glial cells even outnumber neuronal cells by a ratio of 10 to 1. In contrast, only 10% of the cells of the Drosophila nervous system are glia. Glial cells are found in the CNS as well as in the peripheral nervous system (PNS). In the following, we will focus on the development of the embryonic CNS glial cells of Drosophila, the determination and differentiation of which is best understood. Detailed descriptions of peripheral glial cells, and glial cells found in the adult nervous system, have been published (Campos-Ortega and Hartenstein, 1985; Winberg et al., 1992; Giangrande et al., 1993; Giangrande, 1995; Tix et al., 1997; Hartenstein et al.,1998).