Dynamics of an incoherent feedforward loop drive ERK-dependent pattern formation in the early Drosophila embryo

Emily K. Ho, Harrison R. Oatman, Sarah E. McFann, Liu Yang, Heath E. Johnson, Stanislav Y. Shvartsman, Jared E. Toettcher

Research output: Contribution to journalArticlepeer-review


Positional information in development often manifests as stripes of gene expression, but how stripes form remains incompletely understood. Here, we use optogenetics and live-cell biosensors to investigate the posterior brachyenteron (byn) stripe in early Drosophila embryos. This stripe depends on interpretation of an upstream ERK activity gradient and the expression of two target genes, tailless (tll) and huckebein (hkb), that exert antagonistic control over byn. We find that high or low doses of ERK signaling produce transient or sustained byn expression, respectively. Although tll transcription is always rapidly induced, hkb converts graded ERK inputs into a variable time delay. Nuclei thus interpretERK amplitude through the relative timing of tll and hkb transcription. Antagonistic regulatory paths acting on different timescales are hallmarks of an incoherent feedforward loop, which is sufficient to explain byn dynamics and adds temporal complexity to the steady-state model of byn stripe formation. We further show that 'blurring' of an all-or-none stimulus through intracellular diffusion nonlocally produces a byn stripe. Overall, we provide a blueprint for using optogenetics to dissect developmental signal interpretation in space and time.

Original languageEnglish (US)
Article numberdev.201818
JournalDevelopment (Cambridge)
Issue number17
StatePublished - Sep 2023

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Developmental Biology


  • Drosophila development
  • ERK signaling
  • Optogenetics
  • byn stripe


Dive into the research topics of 'Dynamics of an incoherent feedforward loop drive ERK-dependent pattern formation in the early Drosophila embryo'. Together they form a unique fingerprint.

Cite this