Dynamics of BMP signaling in the early Drosophila embryo

• Published in: bioRxiv
• Main Authors: Hadel Y Al Asafen, Aydin Beseli, Sharva Vijayakumar Hiremath, Reeves, Gregory T, Williams, Cranos M
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 21.10.2022
• Subjects: Blastoderm; Bone morphogenetic proteins; Cell signaling; Drosophila; Embryos; Gene expression; Insects; Kinases; Signal transduction
• DOI: 10.1101/2022.10.20.513072

In developing tissues, morphogen gradients are thought to initialize gene expression patterns. However, the relationship between the dynamics of morphogen-encoded signals and gene expression decisions are largely unknown. Here we examine the dynamics of the Bone Morphogenetic Protein (BMP) pathway in Drosophila blastoderm-stage embryos. In this tissue, the BMP pathway is highly dynamic: it begins as a broad and weak signal on the dorsal half of the embryo, then 20-30 min later refines into a narrow, intense peak centered on the dorsal midline. This dynamical progression of the BMP signal raises questions of how it stably activates target genes. Therefore, we performed live imaging of the BMP signal and found that dorsal-lateral cells experience only a short transient in BMP signaling, after which the signal is lost completely. Moreover, we measured the transcriptional response of the BMP target gene pannier in live embryos and found it to remain activated in dorsal-lateral cells, even after the BMP signal is lost. Our findings may suggest that the BMP pathway activates a memory, or "ratchet" mechanism that may sustain gene expression. Competing Interest Statement The authors have declared no competing interest.