glide/gcmIs Expressed and Required in the Scavenger Cell Lineage

Glial cell differentiation inDrosophila melanogasterrequires the activity ofglide/gcm(glial cell deficient/glial cell missing). The role of this gene is to direct the cell fate switch between neurons and glial cells by activating the glial developmental program in multipotent precursor cells of the nervous system. In this paper, we show thatglide/gcmis also expressed and required in the lineage of hemocytes/macrophages, scavenger cells that phagocytose cells undergoing programmed cell death. In addition, we show that, as for glial cells,glide/gcmplays an instructive role in hemocyte differentiation. Interestingly, it has been shown that in the development of the fly adult nervous system the role of scavenger cells is played by glial cells. These data and our findings on the dual role ofglide/gcmindicate that glial cells and hemocytes/macrophages are functionally and molecularly related.