Biomaterial Database

When neural crest and placodes collide: interactions between melanophores and the lateral lines that generate stripes in the salamander Ambystoma tigrinum tigrinum (Ambystomatidae). 1996

D M Parichy

Section of Evolution and Ecology, University of California at Davis 95616, USA.

A prominent element of the early larval pigment pattern in the salamander Ambystoma tigrinum tigrinum (family Ambystomatidae) is a horizontal stripe over the lateral surface of the myotomes where otherwise abundant, neural crest-derived melanophores are not found. This study examines the formation of this "melanophore-free region". When the trunk lateral lines were ablated (by removing cranial lateral line placodes), the melanophore-free region did not form; instead, melanophores populated the middle of the flank and the distribution of yellow, neural chest-derived zanthophores was perturbed. Time-lapse videomicrography demonstrated that during normal development, the melanophore-free region is established because melanophores retreat from the midbody lateral line primordium as it migrates caudally along the inner side of the epidermis. Melanophores do not repopulate the middle of the flank after primordium migration and heterochronic grafting experiments suggest that extracellular factors contribute to maintaining the melanophore-free region during these later stages. Finally, photographic series, microsurgical manipulations, electron microscopy, and staining for molecules of the extracellular matrix (peanut agglutinin-binding components, tenascin, chondroitin sulfate proteoglycans, fibronectin, laminin) suggest that several factors contribute to establishing and maintaining the melanophore-free region, including steric effects of the lateral lines, interactions between melanophores and xanthophores, lateral line-dependent alterations of the subepidermal basement membrane, and a general elaboration of the extracellular matrix. Lateral line effects on melanophores are inferred to be a shared, ancestral feature of pigment pattern development for the families Ambystomatidae and Salamandridae (D.M. Parichy, Dev. Biol. 174, 265-282. 1996). The results of this study thus provide insights into a phylogenetically primitive mechanism for stripe formation, and a context for interpreting evolutionary innovations in pattern-forming mechanisms.

UI	MeSH Term	Description	Entries
D007814	Larva	Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.	Maggots,Tadpoles,Larvae,Maggot,Tadpole
D008547	Melanophores	Chromatophores (large pigment cells of fish, amphibia, reptiles and many invertebrates) which contain melanin. Short term color changes are brought about by an active redistribution of the melanophores pigment containing organelles (MELANOSOMES). Mammals do not have melanophores; however they have retained smaller pigment cells known as MELANOCYTES.	Melanophore
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009432	Neural Crest	The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.	Neural Crest Cells,Neural Fold,Neural Groove,Cell, Neural Crest,Cells, Neural Crest,Crest, Neural,Crests, Neural,Fold, Neural,Folds, Neural,Groove, Neural,Grooves, Neural,Neural Crest Cell,Neural Crests,Neural Folds,Neural Grooves
D002465	Cell Movement	The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.	Cell Migration,Locomotion, Cell,Migration, Cell,Motility, Cell,Movement, Cell,Cell Locomotion,Cell Motility,Cell Movements,Movements, Cell
D002856	Chromatophores	The large pigment cells of fish, amphibia, reptiles and many invertebrates which actively disperse and aggregate their pigment granules. These cells include MELANOPHORES, erythrophores, xanthophores, leucophores and iridiophores. (In algae, chromatophores refer to CHLOROPLASTS. In phototrophic bacteria chromatophores refer to membranous organelles (BACTERIAL CHROMATOPHORES).)	Chromatophore
D004625	Embryo, Nonmammalian	The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.	Embryonic Structures, Nonmammalian,Embryo, Non-Mammalian,Embryonic Structures, Non-Mammalian,Nonmammalian Embryo,Nonmammalian Embryo Structures,Nonmammalian Embryonic Structures,Embryo Structure, Nonmammalian,Embryo Structures, Nonmammalian,Embryo, Non Mammalian,Embryonic Structure, Non-Mammalian,Embryonic Structure, Nonmammalian,Embryonic Structures, Non Mammalian,Embryos, Non-Mammalian,Embryos, Nonmammalian,Non-Mammalian Embryo,Non-Mammalian Embryonic Structure,Non-Mammalian Embryonic Structures,Non-Mammalian Embryos,Nonmammalian Embryo Structure,Nonmammalian Embryonic Structure,Nonmammalian Embryos,Structure, Non-Mammalian Embryonic,Structure, Nonmammalian Embryo,Structure, Nonmammalian Embryonic,Structures, Non-Mammalian Embryonic,Structures, Nonmammalian Embryo,Structures, Nonmammalian Embryonic
D005109	Extracellular Matrix	A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.	Matrix, Extracellular,Extracellular Matrices,Matrices, Extracellular
D000557	Ambystoma	A genus of the Ambystomatidae family. The best known species are the axolotl AMBYSTOMA MEXICANUM and the closely related tiger salamander Ambystoma tigrinum. They may retain gills and remain aquatic without developing all of the adult characteristics. However, under proper changes in the environment they metamorphose.	Amblystoma,Ambystoma tigrinum,Tiger Salamander,Amblystomas,Ambystomas,Salamander, Tiger,Salamanders, Tiger,Tiger Salamanders
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia