Reduced responses to light pulses in jet mutant flies. (A) Behavioral response to phase-delaying and phase-advancing light pulses. All differences between control and mutant flies for both alleles and both zeitgeber times (ZTs) were significant [P < 0.0001 by analysis of variance (ANOVA)]. In this and subsequent figures, error bars denote SEM. (B) Rescue of reduced light sensitivity of jet mutants with a UAS-jet transgene. Phase delays in response to light pulses at ZT 16 in jetc flies with a UAS-jet transgene and either a cry- or tim-Gal4 driver were assayed as in (A). Two independent UAS-jet lines, A and B, produced similar results. xP = 0.06, *P < 0.01, **P < 0.001 by ANOVA. (C) Reduced light-dependent degradation of TIM in clock neurons of jetc mutants. Representative TIM staining in small ventral lateral neurons is shown 1 hour after a 2-min light pulse (LP) at ZT 16. TIM staining without LP is shown for comparison; 8 to 10 fly brains were examined per condition. (D) Rescue of the TIM response to light in clock neurons of jetc mutants with a UAS-jet transgene. jetc mutants with a tim-Gal4 driver alone or with a UAS-jet transgene and a tim-Gal4 driver were assayed as in (C).