= Solution
A <green fluorescent protein> readout follows the corresponding periodically regulated expression, so an individual cell has repeated peaks in <fluorescence>. <Biological translation>, fluorophore maturation, and <protein degradation> introduce a delay and smooth the peaks. For a simple mature <fluorescent reporter> with periodic production $s(t)$, $\dot G=s(t)-\gamma G$ gives $G(t)=G(0)e^{-\gamma t}+\int_0^t e^{-\gamma(t-u)}s(u)\,du$. A long lifetime therefore makes the modulation weak about an accumulated background. <Intrinsic gene-expression noise> makes successive peak heights and periods irregular; averaging cells with unrelated oscillation phases can hide the single-cell oscillations.
Back to article page
