Precision in a rush: Trade-offs between reproducibility and steepness of the hunchback expression pattern
Fly development amazes us by the precision and reproducibility of gene expression, especially since the initial expression patterns are established during very short nuclear cycles.
we discuss possible regulatory strategies, suggesting an important role for additional binding sites, gradients or non-equilibrium binding and modified transcription factor search strategies.
Despite very limited time, organisms develop in reproducible ways. In the early stages of fly development the information about maternal signals is read out in a few minutes to produce steep and precise gene expression patterns.
the current view of one anterior gradient morphogen binding to six binding sites is quantitatively inconsistent with the experimental data given the short readout time, suggesting other regulatory features.
In summary, we show how trade-offs between steep expression profiles and positional resolution influence the possible regulatory modes of hb expression in the short early cell cycles of fly development.
We propose a number of possible solutions from non-equilibrium binding, additional regulatory gradients and binding sites, faster binding rates to epigenetic regulation.
Additional experiments are needed to discriminate between the proposed scenarios.
Common Design 