Published in bio.philica.com
As part of a larger project investigating the role of the FRUITLESS (FRU) transcription factor in the regulation of the yellow gene and, in turn, Drosophila melanogaster male courtship behavior (e.g. Drapeau et al. 2003), we conducted a series of experiments in which we mis- or over-expressed two FRU isoforms. We did this via the bipartite GAL4/UAS expression system (Brand and Perrimon 1993) and UAS-fru constructs “AM” and “BM” described in Drapeau et al. (2003). These express the AM and BM isoforms of FRU protein, respectively.
GAL4 drivers included those with ubiquitous expression patterns throughout the entire body, the central nervous system (CNS), and the muscles, and those with more specific expression patterns within the CNS. We observed a variety of repeatable phenotypes ranging from larval/pupal lethality, to adult developmental defects, to abnormal behavior. When survival was to adulthood, lifespan was often reduced to a few days. Importantly, phenotypes typically differed among AM and BM constructs, strongly suggesting different functions, and indeed different transcription targets of the two isoforms. In some cases, phenotypes also varied between the sexes, implying sex-specific FRU action.
The most interesting observed phenotype occurred with the misexpression of BM in all mature neurons. These flies either could not fly (males) or had severely disrupted flight (females). They also exhibited abnormal “wing out” or “wing flick” behavior, reminiscent of a normal male courtship behavior that FRU controls (Drapeau et al. 2003). Wing morphology appeared normal. We did not observe this when the AM isoform was over-expressed in all neurons, because this genotype is lethal prior to adulthood.
In summary, FRU most likely has numerous and diverse transcriptional targets capable of changing many phenotypes, including sexual behavior.
This laboratory observation is part of a larger body of work on the role of the fruitless gene in the regulation of sexual behavior of Drosophila melanogaster, including the first author’s doctoral dissertation.
Brand, A. H., & Perrimon, N. (1993). Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. Development, 118, 401-415.
Drapeau, M. D., Radovic, A., Wittkopp, P. J., & Long, A. D. (2003). A gene necessary for normal male courtship, yellow, acts downstream of fruitless in the Drosophila melanogaster larval brain. Journal of Neurobiology, 55, 53-72.
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This Observation was published on 19th June, 2006 at 19:15:35 and has been viewed 8200 times.
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The full citation for this Observation is:|
Drapeau, M. (2006). Fly flight inhibition by misexpression of a FRU isoform. PHILICA.COM Observation number 11.
1 added 29th August, 2006 at 21:13:47
I note that an article supporting my Philica Observation was recently published. The abbreviated reference for the paper is:
J.C. Billeter et al. 2006. “Isoform-specific control of male neuronal differentiation and behavior in Drosophila by the fruitless gene” Current Biology 16: 1063.