Related Experiment Video
Updated: Jan 27, 2026
11:52
Temporal Ordering of Dynamic Expression Data from Detailed Spatial Expression Maps
Published on: February 9, 2017
6.5K
Dynamic Hh signalling can generate temporal information during tissue patterning
Diana García-Morales1, Tomás Navarro1, Antonella Iannini1
1CABD (CSIC-Universidad Pablo de Olavide-Junta de Andalucía), GEM-DMC2 Unit, Campus UPO, 41013 Seville, Spain.
Development (Cambridge, England)
|March 29, 2019
Summary
Ocellar cells in Drosophila use the Hedgehog (Hh) morphogen gradient not just for spatial, but also for temporal patterning. This allows for precise, time-based differentiation of photoreceptors in the developing visual system.
Area of Science:
- Developmental biology
- Cell signaling
- Neuroscience
Background:
- Cellular differentiation relies on spatial and temporal information exchange.
- Morphogens create concentration gradients that cells interpret for gene expression and behavior.
- The potential for morphogen gradients to encode temporal information remains largely unexplored.
Purpose of the Study:
- To investigate the role of Hedgehog (Hh) signaling in the temporal patterning of the Drosophila ocellar retina.
- To determine if morphogen gradients can function as developmental time cues.
Main Methods:
- Studied the developmental role of Hh in the Drosophila ocellar retina.
- Analyzed the non-linear gradient of Hh as a temporal cue.
- Investigated the mathematical transformation of the Hh gradient by ocellar cells.
Main Results:
- Ocellar cells utilize the non-linear Hh gradient as a temporal cue.
- Cells perform a biological logarithmic transformation of the Hh concentration gradient.
- This mechanism decodes the diffusing morphogen into a constant-speed wave of differentiating photoreceptors.
Conclusions:
- Morphogen gradients can convey developmental time, not just spatial information.
- The Hh gradient in the ocellar retina acts as a temporal signal for photoreceptor differentiation.
- This provides a novel mechanism for generating precise temporal patterns during development.
Related Concept Videos
01:13¹H NMR Signal Multiplicity: Splitting Patterns
6.5K
When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
6.5K
01:06Fixed Action Patterns
17.6K
A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs.
17.6K
01:19Contact-dependent Signaling
46.9K
Contact-dependent signaling, as the name suggests, requires that communicating cells be in direct contact with each other. This is achieved either through receptor-ligand interactions or by specialized cytoplasmic channels that allow the flow of small molecules between cells. In animal cells, channels called gap junctions facilitate contact-dependent signaling in certain tissues, whereas, plasmodesmata perform a similar function in plants.
Gap Junctions
In animal cells, gap junctions are formed...
Gap Junctions
In animal cells, gap junctions are formed...
46.9K
01:24Intracellular Signaling Cascades
53.5K
Once a ligand binds to a receptor, the signal is transmitted through the membrane and into the cytoplasm. The continuation of a signal in this manner is called signal transduction. Signal transduction only occurs with cell-surface receptors, which cannot interact with most components of the cell, such as DNA. Only internal receptors can interact directly with DNA in the nucleus to initiate protein synthesis. When a ligand binds to its receptor, conformational changes occur that affect the...
53.5K
02:03What is Cell Signaling?
130.0K
Despite the protective membrane that separates a cell from the environment, cells need the ability to detect and respond to environmental changes. Additionally, cells often need to communicate with one another. Unicellular and multicellular organisms use a variety of cell signaling mechanisms to communicate to respond to the environment.
130.0K
02:20Dynamic Equilibrium
62.1K
A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When the rates of the forward and reverse reactions are equal, the concentrations of the reactant and product species remain constant over time and the system is at equilibrium. A special double arrow is used to emphasize the reversible nature of the reaction. The relative concentrations of reactants and products in equilibrium systems vary greatly;...
62.1K