The Function of theDrosophila argosGene Product in the Development of Embryonic Chordotonal Organs

Abstract

We characterized the embryonic expression pattern and mutant phenotypes of theDrosophilageneargos,which encodes a secreted protein with an epidermal growth factor motif. Theargosnull mutation caused an increase in chordotonal (Ch) organs in both the thoracic and the abdominal segments, whereas overexpression of theargosgene resulted in a decrease in these organs. We showed that theargostranscripts are expressed transiently in the cells surrounding the Ch organ precursor and that the generhomboid(rho), which is involved in the regulation of the number of Ch organs, acts epistatically toargosin this event. Our findings suggest thatargosplays a role in Ch organ precursor formation and regulates the final number of Ch organs.