The zebrafish adult pigment pattern has emerged as a useful model for understanding the development and evolution of adult form as well as pattern-forming mechanisms more generally. In this species, a series of horizontal melanophore stripes arises during the larval-to-adult transformation, but the genetic and cellular bases for stripe formation remain largely unknown. Here, we show that the se...

We examined the distribution of iridophores in the skin of the zebrafish and the effects of a neurotransmitter and hormones on the cells. In the skin of deep blue stripe areas, motile iridophores are distributed over the layer of melanophores, while in the dorsal skin, such cells underlie melanophores and xanthophores. These iridophores assume blue coloration in physiological saline probably th...

Growth hormone (GH), prolactin (PRL), and somatolactin (SL) are members of GH/PRL superfamily. These hormones are involved in the regulation of an array of physiological processes, including growth, lactation, and osmoregulation. While recent evidence has shown the GH, PRL, and SL gene transcripts and protein products are expressed during early zebraWsh development, their functions at this time...

We report the isolation and identification of a new mutation affecting pigment cell fate in the zebrafish neural crest. Homozygous nacre (nac(w2)) mutants lack melanophores throughout development but have increased numbers of iridophores. The non-crest-derived retinal pigment epithelium is normal, suggesting that the mutation does not affect pigment synthesis per se. Expression of early melanob...

Medaka is emerging as a model organism for the study of vertebrate development and genetics, and its effectiveness in forward genetics should prove equal to that of zebrafish. Here, we identify by positional cloning a gene responsible for the medaka i-3 albino mutant. i-3 larvae have weakly tyrosinase-positive cells but lack strongly positive and dendritic cells, suggesting loss of fully differ...

Major signaling cascades have been shown to play a role in the regulation of intracellular organelle transport . Aggregation and dispersion of pigment granules in melanophores are regulated by the second messenger cAMP through the protein kinase A (PKA) signaling pathway ; however, the exact mechanisms of this regulation are poorly understood. To study the role of signaling molecules in the reg...

The organization of the cytoplasm is regulated by molecular motors, which transport organelles and other cargoes along cytoskeleton tracks. In this work, we use single particle tracking to study the in vivo regulation of the transport driven by myosin-V along actin filaments in Xenopus laevis melanophores. Melanophores have pigment organelles or melanosomes, which, in response to hormones, disp...