Re-examining the Stability of the Bicoid Morphogen Gradient

In a recent pair of papers published in Cell, Gregor et al. provide an unprecedented glimpse into the dynamics of Bicoid (Bcd), a classical morphogen whose graded distribution along the anterior-posterior axis of the Drosophila embryo provides a key polarity cue guiding embryonic patterning (Gregor et al., 2007a, 2007b). With their data, the authors challenge the prevailing view of how the Bicoid gradient is established and interpreted. However, our reanalysis of their data demonstrates that their findings are consistent with the well-accepted paradigm of diffusion-based patterning and provides further support for the notion that the Bicoid profile is decoded prior to reaching its steady state (Bergmann et al., 2007).