We are also characterizing mutations from a previous genetic screen in which sibling neuron fates were perturbed, to identify genes involved in spindle orientation and Numb localization within mitotic GMCs. We are interested in how the regulation of these genes has evolved between fly and vertebrates. Finally, we are using microarrays to look for transcriptional targets of Vnd and Ind proteins. A long-term interest of our lab has been to understand how neural diversity is generated. To answer the second question, we are studying how asymmetry proteins regulate glial development.
Several neuroblasts produce a mixed lineage, first producing glia and then generating neurons.
These neuroblasts have low levels of gcm mRNA during their early phase of gliogenesis, which is upregulated in the daughter cells that make glia and downregulated in the neuroblast just as it switches to producing neurons. A final project in our lab is to study how a single neuroblast produces a different GMC with each cell cycle. We have done lineage studies to identify the neurons and glia produced by every single embryonic neuroblast and have begun to define the birth order of all progeny for selected neuroblasts. We have found two neurons in this lineage that undergo programmed cell death, and this death occurs in response to Notch signaling. We are characterizing expression patterns of numerous genes within this simple lineage and have begun exploring mutant phenotypes for many of these genes.