This framework has several interesting consequences, implying that average Erk activity is what encodes memory of tissue size, while the Erk gradients have invariant properties, i.e. the ratio of Erk activity at the tip vs the amputation plane is the same for all rays at all times. - ThreadSky

ditalialab.bsky.social • 64 days ago

This framework has several interesting consequences, implying that average Erk activity is what encodes memory of tissue size, while the Erk gradients have invariant properties, i.e. the ratio of Erk activity at the tip vs the amputation plane is the same for all rays at all times.

Comments

ditalialab.bsky.social•64 days ago

To be more clear, this is the behavior of the gradients across space and time

ditalialab.bsky.social•64 days ago

An interesting property of these gradients is that they can be thought of as rulers measuring how much growth has occurred and how much is still left to occur. But how are these gradients built? In collaboration with Massimo Vergassola, we developed a mathematical model for the gradients

ditalialab.bsky.social•64 days ago

Based on several estimates, we concluded that diffusion was unlikely to play a major role in the establishment of the gradients. Thus we focused on the role of advection (transport) of ligands by tissue growth and found that such a model could perfectly explain our data

ditalialab.bsky.social•64 days ago

Two conditions have to be met for the model to work. First, the lifetime of the ligand controlling the gradient must be 4 days or longer. Second, the size of the source region (at the tip of the regenerate) producing the ligands must scale with the amount of tissue removed.

ditalialab.bsky.social•64 days ago

We supported the first condition by experiments blocking protein synthesis and estimating that Erk activity is retained at normal levels for at least 12 hours (longer inhibition were toxic) arguing for a lifetime of few days.

ditalialab.bsky.social•64 days ago

Next, we turned our attention to the ligand producing source and specifically to the cells of the basal epidermis that produce Fgf20a, which is upstream in the regeneration cascade and absolutely required. We found that the number of Fgf20a producing cells scale with the amount of tissue removed.

Comments

Posting Rules

Reply