In the embryo, EcollacZ^gcm-rA87 drives expression in the peritracheal cells and in two symmetrical clusters in the procephalic mesoderm. The cells in the latter do not colocalise with elav or pros.

EcollacZ^gcm-rA87 labels the younger glial cells that are generated postembryonically in the larval brain, including the glial cells produced by type II (secondary) neuroblasts. At the early third instar when cells first start expressing EcollacZ^gcm-rA87 they might also co-express the neuronal markers elav or pros.

In addition to expression in glial precursor cells and lamina precursor cells in the third instar larval optic lobe, reporter expression is observed in medulla neuropil glial cells.

In the larval visual system, EcollacZ^gcm-rA87 is expressed not only in specific glial subtypes, but also in the lineage that gives rise to lamina neurons. EcollacZ^gcm-rA87 is expressed in epithelial glia, marginal glia, and some medulla neuropil glia, but not in medulla or lobula glia.

Enhancer trap expression is observed at embryonic stage 8 in the procephalic mesoderm. Later, it is observed in all hemocytes.

Enhancer trap expression first occurs in an anterior ventral patch in the cellular blastoderm embryo. During gastrulation, these cells invaginate at the end of the ventral furrow just anterior to the cephalic furrow in an area that gives rise to the cephalic mesoderm. During stages 11-12, in each hemisegment, sequential and transient expression occurs in two patches of 3-5 ectodermal cells. From each patch, a single large blast cell delaminates and maintains expression. These are tentatively identified as the peripheral glioblast and the longitudinal glioblast. By late stage 11, enhancer trap expression occurs in all of the progeny of these glioblasts as well as in additional glial cells. In the brain lobes, a complex pattern of expression is seen through stage 17. In the PNS, expression occurs in all repo-positive glia along peripheral axon pathways and associated with sensory organs.

By late stage 11, enhancer trap expression occurs in all of the progeny of these glioblasts as well as in additional glial cells. In the brain lobes, a complex pattern of expression is seen through stage 17. In the PNS, expression occurs in all repo-positive glia along peripheral axon pathways and associated with sensory organs.