Embryonic Expression of the Divergent Drosophila beta 3-Tubulin Isoform Is Required for Larval Behavior

• Published in: Genetics (Austin) 2001-05, Vol.158 (1), p.253-263
• Main Authors: Dettman, R W, Turner, FR, Hoyle, H D, Raff, E C
• Format: Article
• Language: English
• Subjects: b3-tubulin gene; Drosophila; proprioreception
• ISSN: 0016-6731

We have sought to define the developmental and cellular roles played by differential expression of distinct beta -tubulins. Drosophila beta 3-tubulin ( beta 3) is a structurally divergent isoform transiently expressed during midembryogenesis. Severe beta 3 mutations cause larval lethality resulting from failed gut function and consequent starvation. However, mutant larvae also display behavioral abnormalities consistent with defective sensory perception. We identified embryonic beta 3 expression in several previously undefined sites, including different types of sensory organs. We conclude that abnormalities in foraging behavior and photoresponsiveness exhibited by prelethal mutant larvae reflect defective beta 3 function in the embryo during development of chordotonal and other mechanosensory organs and of Bolwig's organ and nerve. We show that microtubule organization in the cap cells of chordotonal organs is altered in mutant larvae. Thus transient zygotic beta 3 expression has permanent consequences for the architecture of the cap cell microtubule cytoskeleton in the larval sensilla, even when beta 3 is no longer present. Our data provide a link between the microtubule cytoskeleton in embryogenesis and the behavioral phenotype manifested as defective proprioreception at the larval stage.