|Ph.D Student||Kenyagin Dorit|
|Subject||Studying the Developmental Roles of the Drosophila Fer3, a|
Proneural-Like Basic Helix-Loop-Helix Protein
|Department||Department of Medicine||Supervisor||Professor Adi Salzberg|
fer3 is a newly identified basic-Helix-Loop-Helix gene that is expressed specifically in the embryonic central nervous system (CNS). It shows high structural similarity to the proneural genes atonal, achaete and scute.
In this work we present genetic evidence for the ability of fer3 to act as a proneural gene in-vivo. We show that fer3 phenocopies, and can substitute for, the proneural actitvity of achaete and scute in the adult peripheral nervous system (PNS), as indicated by its ability to induce the formation of ectopic sensory bristles in a wild type or an achaete- scute- mutant background. This phenotype depends on the dose of Daughterless, suggesting that Fer3 interacts with Daughterless in-vivo. In addition, fer3, and more so an obligatory activating form of fer3, vp16-fer3, mimic the proneural activity of atonal, by inducing the formation of ectopic chordotonal neurons in the embryonic PNS. In contrast, an obligatory repressing form of fer3, en-fer3, phenocopies atonal loss-off-function.
We also present evidence for the role of Fer3 in the attraction machinery of the commissural axons toward the midline. We found that few of the fer3-expressing cells are commisural interneurons. Moreover, ubiquitous expression of fer3 in the developing CNS causes an abnormal attraction of CNS axons to the midline, whereas ectopic expression of the dominant negative form of fer3 leads to a reduction in their number in the posterior commissure.