Signaling Dynamics Control Cell Fate in the Early Drosophila Embryo

Johnson, Heath E.; Toettcher, Jared E.

doi:10.1016/j.devcel.2019.01.009

Cited by 121 publications

(127 citation statements)

References 50 publications

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“…While several studies have focused on the mechanisms controlling Notch activation by ligand endocytosis [5][6][7][8][9], knowledge about the activation of Notch targets by cleaved NICD and the dynamics involved remains limited [10][11][12][13][14]. More broadly, the role of signal dynamics in controlling developmental processes and tissue differentiation is only partially understood [15][16][17][18][19]. In this study, we employed optogenetics to modulate Notch signalling during Drosophila embryonic development in order to characterize its dynamic regulation and input-output relationship during tissue differentiation in real time.…”

Section: Introductionmentioning

confidence: 99%

Optogenetic inhibition of Delta reveals digital Notch signalling output during tissue differentiation

et al. 2019

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Spatio‐temporal regulation of signalling pathways plays a key role in generating diverse responses during the development of multicellular organisms. The role of signal dynamics in transferring signalling information in vivo is incompletely understood. Here, we employ genome engineering in Drosophila melanogaster to generate a functional optogenetic allele of the Notch ligand Delta (opto‐Delta), which replaces both copies of the endogenous wild‐type locus. Using clonal analysis, we show that optogenetic activation blocks Notch activation through cis‐inhibition in signal‐receiving cells. Signal perturbation in combination with quantitative analysis of a live transcriptional reporter of Notch pathway activity reveals differential tissue‐ and cell‐scale regulatory modes. While at the tissue‐level the duration of Notch signalling determines the probability with which a cellular response will occur, in individual cells Notch activation acts through a switch‐like mechanism. Thus, time confers regulatory properties to Notch signalling that exhibit integrative digital behaviours during tissue differentiation.

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Section: Introductionmentioning

confidence: 99%

Optogenetic inhibition of Delta reveals digital Notch signalling output during tissue differentiation

et al. 2019

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“…We then monitored tissue movements during gastrulation in the presence and absence of blue light to assess whether optogenetic stimulation could compensate for the loss of terminal signaling in each case ( Figure S1). Terminal signaling is required for invagination of the posterior midgut during gastrulation, and we previously found that illuminating OptoSOS embryos expands the domain of contractile midgut tissue across more than 80% of the embryo (18). All three alleles failed to undergo posterior midgut invagination in the dark, indicative of strong loss-of-function of terminal signaling (Figure S1).…”

Section: Establishing Optogenetic Ras As the Sole Source Of Terminalmentioning

confidence: 84%

“…Second, well-characterized optogenetic tools are already available to control the Ras/Erk pathway (16,17), one of the major downstream effector pathways of terminal signaling. Applied to Drosophila development, we found that blue light illumination can be used to drive high, uniform levels of Erk phosphorylation in OptoSOSexpressing embryos and expand the expression domains of terminal signaling-associated genes (18,19). A crucial attribute of this optogenetic system is that it directly activates Ras, rendering it independent of upstream receptor-level stimulation (Figure 1B).…”

Section: Establishing Optogenetic Ras As the Sole Source Of Terminalmentioning

confidence: 98%

Optogenetic rescue of a developmental patterning mutant

Johnson¹,

Shvartsman²,

Toettcher³

2019

Preprint

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Animal embryos are partitioned into spatial domains by complex patterns of signaling and gene expression, yet it is still largely unknown what features of a developmental signal are essential.Part of the challenge arises because it has been impossible to "paint" arbitrary signaling patterns on an embryo to test their sufficiency. Here we demonstrate exactly this capability by combining optogenetic control of Ras/Erk signaling with the genetic loss of terminal signaling in early Drosophila embryos. Simple all-or-none light inputs at the embryonic termini were able to completely rescue normal development, generating viable larvae and fertile adults from this otherwise-lethal genetic mutant. Systematically varying illumination parameters further revealed that at least three distinct developmental programs are triggered by different cumulative doses of Erk. These results open the door to the targeted design of complex morphogenetic outcomes as well as the ability to correct patterning errors that underlie developmental defects. SummarySpatial gradients of protein activity pattern all developing embryos. But which features of these patterns are essential and which are dispensable for development? Answering this question has been deceptively difficult, due to the difficulty of shaping spatial gradients using chemical or genetic perturbations. Johnson and colleagues use optogenetics to fully restore normal embryo development with a pattern of light, opening the door to complete control over spatial organization in developing and engineered tissues.

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“…Evolved LOV (eLOV) was amplified from a synthetic gBlock from IDT based on sequence from the previous work 24 . The degron sequence (GRLYEFRLMMTFSGLNRGFAYARYS) was a gift from Dr. Jing Yang at the University of Illinois Urbana-Champaign.…”

Section: Plasmid Constructionmentioning

confidence: 99%

“…This strategy has been widely used to control target protein activity by protein translocation [4][5][6][7] , protein caging [8][9][10][11] , sequestration 12,13 , clustering 14,15 , induced avidity [16][17][18] or allostery 19,20 . Successful application of non-neuronal optogenetics in multicellular organisms has provided new insights into cell fate determination during embryonic development [21][22][23][24][25][26] . Most of these systems, however, require target-specific protein engineering and often cannot be generalized to control a broader class of proteins.…”

Section: Introductionmentioning

confidence: 99%

Repurposing protein degradation for optogenetic modulation of protein activities

Mondal

Krishnamurthy

Sharum

et al. 2019

Preprint

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Non-neuronal optogenetic approaches empower precise regulation of protein dynamics in live cells but often require target-specific protein engineering. To address this challenge, we developed a generalizable light modulated protein stabilization system (GLIMPSe) to control intracellular protein level independent of its functionality. We applied GLIMPSe to control two distinct classes of proteins: mitogen-activated protein kinase phosphatase 3 (MKP3), a negative regulator of the extracellular signal-regulated kinase (ERK) pathway, as well as a constitutively active form of MEK (CA MEK), a positive regulator of the same pathway. Kinetics study showed that light-induced protein stabilization could be achieved within 1 minute of blue light stimulation.GLIMPSe enables target-independent optogenetic control of protein activities and therefore minimizes the systematic variation embedded within different photoactivatable proteins. Overall, GLIMPSe promises to achieve light-mediated post-translational stabilization of a wide array of target proteins in live cells.

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Signaling Dynamics Control Cell Fate in the Early Drosophila Embryo

Cited by 121 publications

References 50 publications

Optogenetic inhibition of Delta reveals digital Notch signalling output during tissue differentiation

Optogenetic inhibition of Delta reveals digital Notch signalling output during tissue differentiation

Optogenetic rescue of a developmental patterning mutant

Repurposing protein degradation for optogenetic modulation of protein activities

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