Notch-dependent and -independent transcription are modulated by tissue movements at gastrulation

Abstract

Cells sense and integrate external information from diverse sources that include mechanical cues. Shaping of tissues during development may thus require coordination between mechanical forces from morphogenesis and cell-cell signalling to confer appropriate changes in gene expression. By live-imaging Notch-induced transcription in real time we have discovered that morphogenetic movements during Drosophila gastrulation bring about an increase in activity-levels of a Notch responsive enhancer. Mutations that disrupt the timing of gastrulation resulted in concomitant delays in transcription up-regulation that correlated with the start of mesoderm invagination. As a similar gastrulation-induced effect was detected when transcription was elicited by the intracellular domain NICD, it cannot be attributed to forces exerted on Notch receptor activation. A Notch independent vnd enhancer also exhibited a modest gastrulation-induced activity increase in the same stripe of cells. Together, these observations argue that gastrulation-associated forces act on the nucleus to modulate transcription levels. This regulation was uncoupled when the complex linking the nucleoskeleton and cytoskeleton (LINC) was disrupted, indicating a likely conduit. We propose that the coupling between tissue level mechanics, arising from gastrulation, and enhancer activity represents a general mechanism for ensuring correct tissue specification during development and that Notch dependent enhancers are highly sensitive to this regulation.

A spatiotemporal Notch interaction map from plasma membrane to nucleus

“…Third, we found that NICD2 entered a nuclear microenvironment enriched in components associated with a transcriptional response as early as 30 to 45 min after GSI washout and that the molecular neighborhood associated with NICD2 persisted through the final 4-hour time point. This timing of transcriptional induction is consistent with previous real-time luciferase complementation studies using ectopic NOTCH1 and RBPJ expression ( 11 ) and with the onset and duration of Notch-induced transcription in fly models and in cancer cells ( 59 , 63 – 65 ). In addition to MAML1, the nuclear proteins most rapidly recruited to NICD2 were CREBBP/p300, a well-established partner of MAML1 in NICD-dependent transcriptional induction ( 57 , 58 , 66 , 67 ), and components of the BAF chromatin remodeling complex.…”

A Spatiotemporal Notch Interaction Map from Membrane to Nucleus

“…No reuse allowed without permission. real-time luciferase complementation studies using ectopic Notch1 and RBPJ expression (Ilagan et al, 2011) and with the onset and duration of Notch-induced transcription in fly models and in cancer cells (Castel et al, 2013;Falo-Sanjuan & Bray, 2022;Housden et al, 2013;Wang et al, 2014). In addition to MAML1, the nuclear proteins most rapidly recruited to NICD2 are CREBBP/p300, a well-established partner of MAML1 in NICD-dependent transcriptional induction (Fryer et al, 2004;Fryer et al, 2002;Oswald et al, 2001;Wallberg et al, 2002), and components of the BAF chromatin remodeling complex.…”

Temporal Dynamics and Stoichiometry in Notch Signaling - from Notch Synaptic Complex Formation to NICD Nuclear Entry

“…NICD can access the nucleus within 30 min of ψ-secretase inhibitor removal (Martin et al, 2023) and can induce a transcriptional response in the nucleus within 60 min of Notch activation (Falo-Sanjuan & Bray, 2022; Ilagan et al, 2011). To quantify the amount of N2- C entering nuclei after cell-cell contact, we paired and imaged sender and receiver cells immediately (1-5 min) and 60 min after cell contact.…”