Quantification of Clock Gene mRNA Expression
mRNA expression of cycling genes making up the circadian clock in flies was measured by northern blot or RNase protection from two time-course experiments (one of which is shown in Figure S2). An average of the normalized values was obtained and plotted. Genes assayed are indicated to the right of their respective profiles. RNA profiles on the left are from 12 h/12 h, light/dark cycles (LD, indicated by alternating open and closed horizontal bars), right-side profiles are from DD time courses (constant darkness with subjective day indicated by hatched bar). Numbers on the vertical axes indicate relative expression (maximal expression in wild type is 1.0). Numbers on the horizontal axes indicate time (hour within a 24-h cycle) when RNA was collected. Blue, wild-type (wt) time courses; pink, time courses from flies homozygous for one perΔS transgene (per0;perΔSx1); and yellow, time courses from flies homozygous for two perΔS transgenes (per0;perΔSx2). For (K) and (L), the green line represents the endogenous per RNA present in the per0 background, to which the levels were normalized. Notice the change in the scale due to the increased expression of perΔS RNA. Error bars show square root of variance from two independent samplings.