Ho Emily K, Kim-Yip Rebecca P, Simpkins Alison G, Farahani Payam E, Oatman Harrison R, Posfai Eszter, Shvartsman Stanislav Y, Toettcher Jared E
Department of Molecular Biology, Princeton University, Princeton 08544.
Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton 08544.
bioRxiv. 2025 Jan 7:2025.01.06.631605. doi: 10.1101/2025.01.06.631605.
A lack of tools for detecting receptor activity has limited our ability to fully explore receptor-level control of developmental patterning. Here, we extend a new class of biosensors for receptor tyrosine kinase (RTK) activity, the pYtag system, to visualize endogenous RTK activity in . We build biosensors for three RTKs that function across developmental stages and tissues. By characterizing Torso::pYtag during terminal patterning in the early embryo, we find that Torso activity differs from downstream ERK activity in two surprising ways: Torso activity is narrowly restricted to the poles but produces a broader gradient of ERK, and Torso activity decreases over developmental time while ERK activity is sustained. This decrease in Torso activity is driven by ERK pathway-dependent negative feedback. Our results suggest an updated model of terminal patterning where a narrow domain of Torso activity, tuned in amplitude by negative feedback, locally activates signaling effectors which diffuse through the syncytial embryo to form the ERK gradient. Altogether, this work highlights the usefulness of pYtags for investigating receptor-level regulation of developmental patterning.
缺乏用于检测受体活性的工具限制了我们全面探索发育模式形成中受体水平控制的能力。在此，我们将一类用于受体酪氨酸激酶（RTK）活性的新型生物传感器——pYtag系统进行扩展，以可视化[具体生物或组织]中的内源性RTK活性。我们构建了用于三种在发育阶段和组织中均发挥作用的RTK的生物传感器。通过在早期胚胎的末端模式形成过程中对Torso::pYtag进行表征，我们发现Torso活性在两个令人惊讶的方面与下游ERK活性不同：Torso活性被严格限制在两极，但产生更广泛的ERK梯度，并且Torso活性在发育过程中下降，而ERK活性则持续存在。Torso活性的这种下降是由ERK途径依赖性负反馈驱动的。我们的结果提示了一种更新的末端模式形成模型，即由负反馈调节幅度的狭窄Torso活性域局部激活信号效应物，这些效应物通过合胞体胚胎扩散以形成ERK梯度。总之，这项工作突出了pYtag在研究发育模式形成的受体水平调控方面的有用性。
