scholarly journals Homotypic cell competition regulates proliferation and tiling of zebrafish pigment cells during colour pattern formation

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Brigitte Walderich ◽  
Ajeet Pratap Singh ◽  
Prateek Mahalwar ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Pattern Formation ◽  
Pigment Cells ◽  
Colour Pattern ◽  
Cell Competition

Reorganization of membrane contacts prior to apoptosis in the Drosophila retina: the role of the IrreC-rst protein

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1931-1940 ◽  
Author(s):  
C. Reiter ◽  
T. Schimansky ◽  
Z. Nie ◽  
K.F. Fischbach
Keyword(s):  
Pattern Formation ◽  
Pigment Cells ◽  
Immunoglobulin Superfamily ◽  
Specific Cell ◽  
Axonal Pathfinding ◽  
Single Row ◽  
Cell Contacts ◽  
Regulated Expression ◽  
Membrane Contacts

The final step of pattern formation in the developing retina of Drosophila is the elimination of excess cells between ommatidia and the differentiation of the remaining cells into secondary and tertiary pigment cells. Temporally and spatially highly regulated expression of the irregular chiasmC-roughest protein, an adhesion molecule of the immunoglobulin superfamily known to be involved in axonal pathfinding, is essential for correct sorting of cell-cell contacts in the pupal retina without which the ensuing wave of apoptosis does not occur. Irregular chiasmC-roughest accumulates strongly at the borders between primary pigment and interommatidial cells. Mutant and misexpression analysis show that this accumulation of the irregular chiasmC-roughest protein is necessary for aligning interommatidial cells in a single row. This reorganisation is a prerequisite for the identification of death candidates. Irregular chiasmC-roughest function in retinal development demonstrates the importance of specific cell contacts for assignment of the apoptotic fate.

Zebrafish Pigment Pattern Formation: Insights into the Development and Evolution of Adult Form

2019 ◽  
Vol 53 (1) ◽  
pp. 505-530 ◽  
Author(s):  
Larissa B. Patterson ◽  
David M. Parichy
Keyword(s):  
Pattern Formation ◽  
Pigment Cell ◽  
Cell Lineage ◽  
Pigment Cells ◽  
Cellular Interactions ◽  
Lineage Specification ◽  
Pigment Pattern ◽  
Adult Form ◽  
Pattern Development ◽  
Pigment Patterns

Vertebrate pigment patterns are diverse and fascinating adult traits that allow animals to recognize conspecifics, attract mates, and avoid predators. Pigment patterns in fish are among the most amenable traits for studying the cellular basis of adult form, as the cells that produce diverse patterns are readily visible in the skin during development. The genetic basis of pigment pattern development has been most studied in the zebrafish, Danio rerio. Zebrafish adults have alternating dark and light horizontal stripes, resulting from the precise arrangement of three main classes of pigment cells: black melanophores, yellow xanthophores, and iridescent iridophores. The coordination of adult pigment cell lineage specification and differentiation with specific cellular interactions and morphogenetic behaviors is necessary for stripe development. Besides providing a nice example of pattern formation responsible for an adult trait of zebrafish, stripe-forming mechanisms also provide a conceptual framework for posing testable hypotheses about pattern diversification more broadly. Here, we summarize what is known about lineages and molecular interactions required for pattern formation in zebrafish, we review some of what is known about pattern diversification in Danio, and we speculate on how patterns in more distant teleosts may have evolved to produce a stunningly diverse array of patterns in nature.

scholarly journals New insight into the molecular mechanism of colour differentiation among floral segments in orchids

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Bai-Jun Li ◽  
Bao-Qiang Zheng ◽  
Jie-Yu Wang ◽  
Wen-Chieh Tsai ◽  
Hsiang-Chia Lu ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Anthocyanin Biosynthesis ◽  
Flower Colour ◽  
Colour Pattern ◽  
Yellow Colour ◽  
Spatiotemporal Expression ◽  
Pigment Distribution ◽  
Colour Patterns ◽  
R2r3 Myb ◽  
Pigment Accumulation

AbstractAn unbalanced pigment distribution among the sepal and petal segments results in various colour patterns of orchid flowers. Here, we explored this type of mechanism of colour pattern formation in flowers of the Cattleya hybrid ‘KOVA’. Our study showed that pigment accumulation displayed obvious spatiotemporal specificity in the flowers and was likely regulated by three R2R3-MYB transcription factors. Before flowering, RcPAP1 was specifically expressed in the epichile to activate the anthocyanin biosynthesis pathway, which caused substantial cyanin accumulation and resulted in a purple-red colour. After flowering, the expression of RcPAP2 resulted in a low level of cyanin accumulation in the perianths and a pale pink colour, whereas RcPCP1 was expressed only in the hypochile, where it promoted α-carotene and lutein accumulation and resulted in a yellow colour. Additionally, we propose that the spatiotemporal expression of different combinations of AP3- and AGL6-like genes might participate in KOVA flower colour pattern formation.

scholarly journals Studies of Turing pattern formation in zebrafish skin

2021 ◽  
Vol 379 (2213) ◽  
Author(s):  
Shigeru Kondo ◽  
Masakatsu Watanabe ◽  
Seita Miyazawa
Keyword(s):  
Pattern Formation ◽  
Diffusion Mechanism ◽  
Model Organism ◽  
Reaction Diffusion ◽  
Cell Interactions ◽  
Pigment Cells ◽  
Turing Pattern ◽  
Reaction Diffusion Model ◽  
Experimental Findings ◽  
Cell Cell

Skin patterns are the first example of the existence of Turing patterns in living organisms. Extensive research on zebrafish, a model organism with stripes on its skin, has revealed the principles of pattern formation at the molecular and cellular levels. Surprisingly, although the networks of cell–cell interactions have been observed to satisfy the ‘short-range activation and long-range inhibition’ prerequisites for Turing pattern formation, numerous individual reactions were not envisioned based on the classical reaction–diffusion model. For example, in real skin, it is not an alteration in concentrations of chemicals, but autonomous migration and proliferation of pigment cells that establish patterns, and cell–cell interactions are mediated via direct contact through cell protrusions. Therefore, the classical reaction–diffusion mechanism cannot be used as it is for modelling skin pattern formation. Various studies are underway to adapt mathematical models to the experimental findings on research into skin patterns, and the purpose of this review is to organize and present them. These novel theoretical methods could be applied to autonomous pattern formation phenomena other than skin patterns. This article is part of the theme issue ‘Recent progress and open frontiers in Turing's theory of morphogenesis’.

scholarly journals Merle allele variations in the Mudi dog breed and their effects on phenotypes

2019 ◽  
Vol 67 (2) ◽  
pp. 159-173 ◽  
Author(s):  
Zsófia Pelles ◽  
András Gáspárdy ◽  
László Zöldág ◽  
Xénia Lénárt ◽  
Nóra Ninausz ◽  
...  
Keyword(s):  
Coat Colour ◽  
Practical Significance ◽  
Pigment Cells ◽  
Colour Pattern ◽  
Sample Collection ◽  
Fragment Analysis ◽  
Sine Insertion ◽  
Dog Breed ◽  
Exact Size ◽  
Auditory Impairments

A retrotransposon insertion in the SILV gene is associated with a peculiar phenotype of dog, known as a merle. It is characterised by various areas of their coat colour becoming diluted due to a malfunction in the eumelanin-producing pigment cells. Recent studies have shown that the exact size of the short interspersed element (SINE) insertion is in correlation with specific phenotypic attributes, but was not able to absolutely confine dogs to a certain colour pattern. Our study focused on the merle variations occurring in the Mudi breed. Altogether, 123 dog samples from 11 countries were tested and genotyped. The exact length of the merle alleles were determined by automated fluorescent capillary fragment analysis. The most frequent merle genotype in this Mudi sample collection was the ‘classic’ merle (m/M: 61.8%), whereas other variants, such as atypical (m/Ma and m/Ma+: 5.7%), harlequin (m/Mh: 13.8%), double merle (M/M: 0.8%) and mosaic profiles (17.9%) were also observed. The practical significance of testing this mutation is that, phenotypically, not only merle dogs are carriers of this insertion, but also the so-called hidden merle individuals (where the merle phenotype is fully covered by the pheomelanin-dominated colouration) are potentially capable of producing unintentionally homozygous ‘double merle’ progeny with ophthalmologic, viability and auditory impairments.

scholarly journals Modelling stripe formation in zebrafish: an agent-based approach

2015 ◽  
Vol 12 (112) ◽  
pp. 20150812 ◽  
Author(s):  
Alexandria Volkening ◽  
Björn Sandstede
Keyword(s):  
Laser Ablation ◽  
Pattern Formation ◽  
Long Range ◽  
Pigment Cell ◽  
Experimental Results ◽  
Fish Growth ◽  
Pigment Cells ◽  
Stripe Pattern ◽  
Agent Based ◽  
Long Range Interactions

Zebrafish have distinctive black stripes and yellow interstripes that form owing to the interaction of different pigment cells. We present a two-population agent-based model for the development and regeneration of these stripes and interstripes informed by recent experimental results. Our model describes stripe pattern formation, laser ablation and mutations. We find that fish growth shortens the necessary scale for long-range interactions and that iridophores, a third type of pigment cell, help align stripes and interstripes.

A comprehensive model for colour pattern formation in butterflies

1990 ◽  
Vol 239 (1294) ◽  
pp. 81-113 ◽  
Keyword(s):  
Pattern Formation ◽  
Reaction Diffusion ◽  
Colour Pattern ◽  
Single Model ◽  
Simple Diffusion ◽  
Taxonomic Relation ◽  
Step Model ◽  
Colour Patterns ◽  
Modelling Effort ◽  
Source Sink

This paper presents an attempt to construct a single model that can account for pattern formation in a very broad diversity of Lepidoptera. A pattern database is developed for 330 genera and 2208 species in the family Nymphalidae. It is argued that because of the close taxonomic relation between these species, and that all have patterns that are readily derived from the homology system known as the nymphalid ground-plan, the whole diversity of patterns in the database should emerge from a single model mechanism, and that most of this diversity should emerge from simple quantitative variations of the parameters of that model. A formal list of desiderata and constraints on any model for colour pattern formation is developed and used as the basis for the present modelling effort. Based on the assumptions of simple diffusion and threshold mech­anisms, a pattern of source-sink distributions is deduced that can gen­erate the diversity of patterns in the database. The adequacy of this source-sink ‘toolbox' is tested by computer simulation; it is shown that a two-gradient model with a simple additive relation between the two gradients suffices to generate nearly the entire diversity of patterns observed. The requisite positions of the sources and sinks of the toolbox, in turn, emerge readily from Meinhardt’s lateral inhibition model for reaction diffusion. Thus a two step model, consisting first of a reaction- diffusion system that sets up a source-sink pattern and is followed by simple diffusion of a morphogen from those sources, appears to be able to generate nearly the entire diversity of colour patterns seen in the Nymphalidae.

scholarly journals A model for colour pattern formation in the butterfly wing of Papilio dardanus

2000 ◽  
Vol 267 (1446) ◽  
pp. 851-859 ◽  
Author(s):  
Toshio Sekimura ◽  
Anotida Madzvamuse ◽  
Andrew J. Wathen ◽  
Philip K. Maini
Keyword(s):  
Pattern Formation ◽  
Colour Pattern ◽  
Butterfly Wing

scholarly journals Influence of survival, promotion, and growth on pattern formation in zebrafish skin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christopher Konow ◽  
Ziyao Li ◽  
Samantha Shepherd ◽  
Domenico Bullara ◽  
Irving R. Epstein
Keyword(s):  
Pattern Formation ◽  
Organizational Behavior ◽  
Long Range ◽  
Reaction Diffusion ◽  
Turing Instability ◽  
Survival Model ◽  
Domain Growth ◽  
Pigment Cells ◽  
Diffusion Scheme ◽  
Experimental Findings

AbstractThe coloring of zebrafish skin is often used as a model system to study biological pattern formation. However, the small number and lack of movement of chromatophores defies traditional Turing-type pattern generating mechanisms. Recent models invoke discrete short-range competition and long-range promotion between different pigment cells as an alternative to a reaction-diffusion scheme. In this work, we propose a lattice-based “Survival model,” which is inspired by recent experimental findings on the nature of long-range chromatophore interactions. The Survival model produces stationary patterns with diffuse stripes and undergoes a Turing instability. We also examine the effect that domain growth, ubiquitous in biological systems, has on the patterns in both the Survival model and an earlier “Promotion” model. In both cases, domain growth alone is capable of orienting Turing patterns above a threshold wavelength and can reorient the stripes in ablated cells, though the wavelength for which the patterns orient is much larger for the Survival model. While the Survival model is a simplified representation of the multifaceted interactions between pigment cells, it reveals complex organizational behavior and may help to guide future studies.

scholarly journals Tight Junction Protein 1a regulates pigment cell organisation during zebrafish colour patterning

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Andrey Fadeev ◽  
Jana Krauss ◽  
Hans Georg Frohnhöfer ◽  
Uwe Irion ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Tight Junction ◽  
Cell Shape ◽  
Pigment Cell ◽  
Tight Junction Protein ◽  
Pigment Cells ◽  
Colour Pattern ◽  
Junction Protein ◽  
Cell Shape Changes ◽  
Crucial Part ◽  
Shape Changes

Zebrafish display a prominent pattern of alternating dark and light stripes generated by the precise positioning of pigment cells in the skin. This arrangement is the result of coordinated cell movements, cell shape changes, and the organisation of pigment cells during metamorphosis. Iridophores play a crucial part in this process by switching between the dense form of the light stripes and the loose form of the dark stripes. Adult schachbrett (sbr) mutants exhibit delayed changes in iridophore shape and organisation caused by truncations in Tight Junction Protein 1a (ZO-1a). In sbr mutants, the dark stripes are interrupted by dense iridophores invading as coherent sheets. Immuno-labelling and chimeric analyses indicate that Tjp1a is expressed in dense iridophores but down-regulated in the loose form. Tjp1a is a novel regulator of cell shape changes during colour pattern formation and the first cytoplasmic protein implicated in this process.

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