Embryos often communicate instructions to their cells using diffusible signaling molecules called morphogens. In textbook models, morphogens diffuse from a localized source to form a concentration gradient, and target cells select fates by measuring the local morphogen concentration. However, natural patterning systems often incorporate numerous co-factors and extensive signaling feedback, suggesting that embryos require additional means of control to generate reliable patterns. This talk will present our recent results that illuminate how additional regulatory features enable robust pattern formation by the morphogen Nodal in zebrafish embryogenesis. Using a series of mutant embryos engineered to have feedback-compromised patterning systems, we demonstrate that simple ligand diffusion and capture is sufficient to explain the formation of normal Nodal signaling patterns. We further demonstrate that embryos regulate pattern features by tuning ligand capture with cell surface receptor complexes. Finally, we show that negative feedback on signaling, though dispensable under normal circumstances, is required to correct perturbations. Collectively, these results establish the Nodal patterning system as an exciting model for robust developmental patterning.
Join Zoom Meeting
https://zoom.us/j/91019034916
Meeting ID: 910 1903 4916
Passcode: 994404
Thesis defence (hybrid):
-------------------------
Join Zoom Meeting
https://zoom.us/j/99549679295
Meeting ID: 995 4967 9295
Passcode: 323624
--------------------------------------------------------------
In this talk, we will describe two independent results based on my thesis. The first is on a unique factorization property for tensor products of parabolic Verma modules. More precisely, we give a
necessary and sufficient condition for when products of characters of two collections of parabolic Verma modules (and their restrictions to some subalgebras of the Cartan subalgebra) are equal. The second part is on the factorization phenomenon of flagged skew Schur polynomials upon twisting the variables by roots of unity. These flagged skew Schur polynomials include an interesting family of Demazure characters as a special case.
-------------------------------------------------------------------