We report the identification and characterization of a new Drosophila clock
-regulated gene, takeout (to). to is a member of a novel gene family and is
implicated in circadian control of feeding behavior. Its gene expression i
s down-regulated in all of the clock mutants tested. In wild-type flies, to
mRNA exhibits daily cycling expression but with a novel phase, delayed rel
ative to those of the better-characterized clock mRNAs, period and timeless
. The E-box-containing sequence in the to promoter shows impressive similar
ities with those of period and timeless. However, our results suggest that
the E box is not involved in the amplitude and phase of the transcriptional
cycling of to. The circadian delayed transcriptional phase is therefore mo
st likely the result of indirect regulation through unknown transcription f
actors.