Characterization of a Novel Circadian Clock Mutant, bowelP

Here, we report characteristics of a novel Drosophila circadian arrhythmic mutant, which is induced by a P-element insertion in the regulatory region of the bowel (brother of Q.dd 9£ith !ntrails limited) gene (hereafter bowf). The mutant flies exhibited arrhythmic circadian locomotor activities and arrhythmic eclosion. At the molecular level, the abnormality of circadian rhythms was resulted from the low levels of both PDF (PIGMENT DISPERSING FACTOR) and TIM (TIMELESS) in the primary pacemaker cells, the small ventro-lateral neurons. Such defective pdf gene expression in bowf mutant was strikingly similar to that shown in dClock'rk and cycle0 mutants - extremely low levels of pdf transcript only in the small ventrolateral neurons. From these mutational effects on both clock gene and clock output gene expression, we propose that the bowel gene might be another central clock component in Drosophila.