Adult Circadian Behavior in Drosophila Requires Developmental Expression of cycle, But Not period
Figure 8
Selective inhibition of cyc01 rescue in the PDF-expressing clock neurons results in behavioral circadian phenotypes.
(A) Example actograms (left) and LD activity profiles (right) representing median locomotor behavior for female elavC155::Gal4; UAS-cyc/CyO; cyc01 flies (abbreviated as cyc01 elav>cyc), which are rescued for cyc expression in postmitotic neurons, versus female elavC155::Gal4; UAS-cyc/Pdf-Gal80; cyc01 flies (abbreviated as cyc01 (elav-Pdf)>cyc), in which transgenic cyc rescue is selectively blocked in the PDF-expressing clock neurons. The activity profiles represent average daily activity (±SEM) indicated by the black line and red shading for the median locomotor activity of cyc01 elav>cyc and cyc01 (elav-Pdf)>cyc flies in the presence of LD cycles. Note that cyc01 (elav-Pdf)>cyc flies exhibit loss of free running rhythms in DD as well as increased activity in anticipation of lights-on and loss of activity in anticipation of lights-off in LD. (B) Stacked bar diagram representing the percentages of female flies with rhythmic, weakly rhythmic, or arrhythmic adult behavior at 25°C DD. Along with cyc01 elav>cyc and cyc01 (elav-Pdf)>cyc flies, the experiment also included non-rescued control flies with an elavC155::Gal4; CyO/Pdf-Gal80; cyc01 genotype (abbreviated as cyc01 (elav-Pdf)>-). For each transgenic combination with cyc01 the number of flies (n) as well as the average (±SEM) circadian period length for rhythmic flies are indicated. Chi-square analysis indicated a highly significant (p<10−9) association between genotype and the percentages of rhythmic, weakly rhythmic, and arrhythmic adults. (C) Bar diagram of the average (±SEM) relative rhythmic power observed among the rhythmic plus weakly rhythmic female flies for each genotype. The number of flies included in this analysis (n) is indicated for each condition. Because all cyc01 (elav-Pdf)>- flies were arrhythmic, a Mann-Whitney rank-sum test was performed to compare the effect on relative rhythmic power of the other two genotypes. As indicated, relative rhythmic power was significantly reduced in cyc01 (elav-Pdf)>cyc flies compared to cyc01 elav>cyc flies (**; p<10−2).