Parichy Lab
Movies

 

On this page are several sets of movies showing adult pigment pattern metamorphosis in wild-type zebrafish, mutant zebrafish, and other species. Each movie is an animation compiled from once or twice daily images of individual fish lasting from 6 to 30 days of development, with images rescaled to correct for growth. Movies are in QuickTime format and may take a few moments to load.

1. Differences in pigment pattern formation between D. rerio and D. albolineatus.
2. Different contributions of latent precursors to adult stripes in D. rerio and D. nigrofasciatus.
3. Failure of pigment pattern metamorphosis in puma mutant D. rerio.
4. Interactions between fms-dependent xanthophores and melanophores in D. rerio stripe development.
5. bonaparte and pissarro requirements for adult stripe development.
6. Pigment pattern remodeling in danios.
7. kit mutants in D. rerio and D. albolineatus reveal evolutionarily conserved, late metamorphic melanophores

 

1. Pigment pattern metamorphosis differs between wild-type zebrafish D. rerio and D. albolineatus.
In D. rerio, numerous melanophores differentiate from latent precursors during metamorphosis and some of these initially dispersed melanophores migrate short distances to sites of stripe formation. In D. albolineatus, there are fewer melanophores owing to increased rates of melanophore death, and directional movements are significantly reduced. We are working to identify the interspecific differences in cellular interactions and pattern-forming cues.
D. rerio
D. albolineatus

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2. Differential deployment of embryonic and post-embryonic melanophore lineages during adult stripe formation.
In D. rerio, the vast majority of adult stripe melanophores develop from latent precursors during metamorphosis. In D. nigrofasciatus, however, fewer melanophores differentiate at metamorphosis; instead, many melanophores that differentiated in embryos to form the early larval pigment pattern are redeployed into the adult stripes. These animations are in reverse, starting with the final adult stripes and going back in time to the early larval pigment pattern. Thus, cells that differentiated during metamorphosis "disappear" in the movies; only in D. nigrofasciatus can many of these cells be traced back to positions in the early larval pigment pattern (a few melanophores in the middle of the flank of D. rerio are actually deep within the fish and do not contribute to the adult pattern). We are currently testing candidate genes for contributing to these species differences.

D. rerio

D. nigrofasciatus
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3. puma mutant decouples pigment pattern and somatic metamorphosis in zebrafish.
Zebrafish mutants provide one way to dissect the mechanisms underlying pigment pattern metamorphosis and latent precursor establishment, maintenance, and recruitment. In puma mutants, the overall somatic larval-to-adult transformation occurs relatively normally, but most adult melanophores fail to develop. Instead, early larval melanophores persist inappropriately on the flank. We are working to clone the gene affected in puma mutants.

wild-type D. rerio (2.8 Mb)

puma mutant D. rerio (2.3 Mb)
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4. Temperature-sensitive alleles reveal cellular interactions essential for adult stripe development and maintenance.
An advantage of zebrafish is that we can readily isolate temperature-sensitive alleles, allowing us to up- or down-regulate protein activity by shifting fish between permissive and restrictive temperatures. We used this approach to show that the fms receptor tyrosine kinase is essential for the development of yellow xanthophores, as well as melanophore stripes. When fms activity is curtailed at any stage, xanthophores die and melanophore stripes degenerate. When fms activity is restored at any stage, xanthophores recover and melanophores organize into stripes.
fms turned off (3.9 Mb)
fms turned on (3.1 Mb)

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5. New mutants affecting pigment pattern metamorphosis.
We are working to clone several additional mutants affecting adult pigment pattern and other traits, including bonaparte and pissarro.
bonaparte (1.9 Mb)
pissarro (2.1 Mb)
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6. Pigment pattern remodeling in danios.
Our studies suggest that a pattern of two or more horizontal stripes represents a basic groundplan for Danio pigment pattern formation, and this groundplan can be remodelled in various ways. One type of modification involves the fission of existing stripes, as well as vertical bridging between stripes. Danio dangila, shown below, shows both processes during the juvenile development of its pigment pattern. We are working to identify the molecular and cellular mechanisms that underlie these pattern modifications.
D. dangila (9.3 Mb)
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7. kit mutants in D. rerio and D. albolineatus reveal evolutionarily conserved, late metamorphic melanophores
In D. rerio, adult pigment pattern formation involves early metamorphic melanophores that arise dispersed over the flank and then migrate into stripes, as well as late metamorphic melanophores that develop already in stripes. Early metamorphic melanophores require the kit receptor tyrosine kinase, as they are ablated in kit mutants. By contrast, late metamorphic melanophores develop independently of kit. To see if distinct kit-dependent and kit-independent melanophores occur in other danios, we isoated a kit mutant in D. albolineatus. These fish develop kit-independent melanophores, demonstratrating the evolutionary conservation of thesemelanophore populations. Interestingly, although D. albolineatus have uniform patterns, kit-independent melanophores in this species develop in stripes, revealing latent stripe forming potential.
Wild-type and kit mutants of D. rerio and D. albolineatus (30.5 Mb)
Wild-type and kit mutants of D. rerio and D. albolineatus (7.5 Mb)
 
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