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Melanocyte Development (melanocyte + development)
Selected AbstractsIris as a recipient tissue for pigment cells: Organized in vivo differentiation of melanocytes and pigmented epithelium derived from embryonic stem cells in vitroDEVELOPMENTAL DYNAMICS, Issue 9 2008Hitomi Aoki Abstract Regenerative transplantation of embryonic stem (ES) cell-derived melanocytes into adult tissues, especially skin that includes hair follicles or the hair follicle itself, generally not possible, whereas that of ES cell-derived pigmented epithelium was reported previously. We investigated the in vivo differentiation of these two pigment cell types derived from ES cells after their transfer into the iris. Melanocytes derived from ES cells efficiently integrated into the iris and expanded to fill the stromal layer of the iris, like those prepared from neonatal skin. Transplanted pigmented epithelium from either ES cells or the neonatal eye was also found to be integrated into the iris. Both types of these regenerated pigment cells showed the correct morphology. Regenerated pigment epithelium expressed its functional marker. Functional blocking of signals required for melanocyte development abolished the differentiation of transplanted melanocytes. These results indicate successful in vivo regenerative transfer of pigment cells induced from ES cells in vitro. Developmental Dynamics 237:2394,2404, 2008. © 2008 Wiley-Liss, Inc. [source] Complementation of melanocyte development in SOX10 mutant neural crest using lineage-directed gene transferDEVELOPMENTAL DYNAMICS, Issue 1 2004Ling Hou Abstract An in vitro gene complementation approach has been developed to dissect gene function and regulation in neural crest (NC) development and disease. The approach uses the avian RCAS virus to express genes in NC cells derived from transgenic mice expressing the RCAS receptor TVA, under the control of defined promoter elements. Constructs for creating TVA transgenic mice were developed using site-specific recombination GATEWAY (GW), compatible vectors that can also be used to facilitate analysis of genomic fragments for transcriptional regulatory elements. By using these GW vectors to facilitate cloning, transgenic mouse lines were generated that express TVA in SOX10-expressing NC stem cells under the control of the Pax3 promoter. The Pax3-tv-a transgene was bred onto a Sox10 -deficient background, and the feasibility of complementing genetic NC defects was demonstrated by infecting the Pax3-tv-a cells with an RCAS- Sox10 expression virus, thereby rescuing melanocyte development of Sox10 -deficient NC cells. This system will be useful for assessing genetic hierarchies in NC development. Developmental Dynamics 229:54,62, 2004. © 2003 Wiley-Liss, Inc. [source] A review of genetic disorders of hypopigmentation: lessons learned from the biology of melanocytesEXPERIMENTAL DERMATOLOGY, Issue 9 2009Clio Dessinioti Abstract:, Inherited diseases of pigmentation were among the first traits studied in humans because of their easy recognition. The discovery of genes that regulate melanocytic development and function and the identification of disease-causative mutations have greatly improved our understanding of the molecular basis of pigmentary genodermatoses and their underlying pathogenetic mechanisms. Pigmentation mutants can account for hypo-/amelanosis, with or without altered melanocyte number, resulting in different phenotypes, such as Waardenburg syndrome, piebaldism, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, oculocutaneous albinism and Griscelli syndrome. In this review, we summarize the basic concepts of melanocyte biology and discuss how molecular defects in melanocyte development and function can result in the development of hypopigmentary hereditary skin diseases. [source] The MITF transcription factor in melanocyte developmentEXPERIMENTAL DERMATOLOGY, Issue 10 2006Eirikur Steingrimsson PhD No abstract is available for this article. [source] Allele-specific genetic interactions between Mitf and Kit affect melanocyte developmentPIGMENT CELL & MELANOMA RESEARCH, Issue 3 2010Bin Wen Summary The tyrosine kinase receptor KIT and the transcription factor MITF, each required for melanocyte development, have been shown to interact functionally both in vitro and in vivo. In vitro, KIT signaling leads to MITF phosphorylation, affecting MITF activity and stability. In vivo, the presence of the Mitf,Mi-wh allele exacerbates the spotting phenotype associated with heterozygosity for Kit mutations. Here, we show that among a series of other Mitf alleles, only the recessive Mitf,mi-bws mimics the effect of Mitf,Mi-wh on Kit. Intriguingly, Mitf,mi-bws is characterized by a splice defect that leads to a reduction of RNAs containing MITF exon 2B which encodes serine-73, a serine phosphorylated upon KIT signaling. Nevertheless, other Mitf alleles that generally affect Mitf RNA levels, or carry a serine-73-to-alanine mutation that specifically reduces exon 2B-containing RNAs, do not show similar interactions with Kit in vivo. We conclude that the recessive Mitf,mi-bws is a complex allele that can display a semi-dominant effect when present in a Kit -sensitized background. We suggest that human disease variability may equally be due to complex, allele-specific interactions between different genes. [source] Timeline and distribution of melanocyte precursors in the mouse heartPIGMENT CELL & MELANOMA RESEARCH, Issue 4 2008Flavia Carneiro Brito Summary Apart from the well-studied melanocytes of the skin, eye and inner ear, another population has recently been described in the heart. In this study, we tracked cardiac melanoblasts using in situ hybridization with a dopachrome tautomerase (Dct) probe and Dct -LacZ transgenic mice. Large numbers of melanoblasts were found in the atrioventricular (AV) endocardial cushions at embryonic day (E) 14.5 and persisted in the AV valves into adulthood. The earliest time Dct -LacZ-positive cells were observed in the AV endocardial cushions was E12.5. Prior to that, between E10.5 and E11.5, small numbers of melanoblasts traveled between the post-otic area and third somite along the anterior and common cardinal veins and branchial arch arteries with other neural crest cells expressing CRABPI. Cardiac melanocytes were not found in the spotting mutants Ednrbs-l/s-l and Kitw-v/w-v, while large numbers were observed in transgenic mice that overexpress endothelin 3. These results indicate that cardiac melanocytes depend on the same signaling molecules known to be required for proper skin melanocyte development and may originate from the same precursor population. Cardiac melanocytes were not found in zebrafish or frog but were present in quail suggesting an association between cardiac melanocytes and four-chambered hearts. [source] Informatic and genomic analysis of melanocyte cDNA libraries as a resource for the study of melanocyte development and functionPIGMENT CELL & MELANOMA RESEARCH, Issue 3 2007Laura L. Baxter Summary As part of the RIKEN mouse encyclopedia project, two cDNA libraries were prepared from melanocyte-derived cell lines, using techniques of full-length clone selection and subtraction/normalization to enrich for rare transcripts. End sequencing showed that these libraries display over 83% complete coding sequence at the 5, end and 96,97% complete coding sequence at the 3, end. Evaluation of the libraries, derived from B16F10Y tumor cells and melan-c cells, revealed that they contain clones for a majority of the genes previously demonstrated to function in melanocyte biology. Analysis of genomic locations for transcripts revealed that the distribution of melanocyte genes is non-random throughout the genome. Three genomic regions identified that showed significant clustering of melanocyte-expressed genes contain one or more genes previously shown to regulate melanocyte development or function. A catalog of genes expressed in these libraries is presented, providing a valuable resource of cDNA clones and sequence information that can be used for identification of new genes important for melanocyte development, function, and disease. [source] Production of Melanocyte-Specific Antibodies to Human Melanosomal Proteins: Expression Patterns in Normal Human Skin and in Cutaneous Pigmented LesionsPIGMENT CELL & MELANOMA RESEARCH, Issue 4 2001Victoria Virador Multiple factors affect skin pigmentation, including those that regulate melanocyte and/or keratinocyte function. Such factors, particularly those that operate at the level of the melanosome, are relatively well characterized in mice, but the expression and function of structural and enzymatic proteins in melanocytes in human skin are not as well known. Some years ago, we generated peptide-specific antibodies to murine melanosomal proteins that proved to be instrumental in elucidating melanocyte development and differentiation in mice, but cross-reactivity of those antibodies with the corresponding human proteins often was weak or absent. In an effort to characterize the roles of melanosomal proteins in human skin pigmentation, and to understand the underlying mechanism(s) of abnormal skin pigmentation, we have now generated polyclonal antibodies against the human melanocyte-specific markers, tyrosinase, tyrosinase-related protein 1 (TYRP1), Dopachrome tautomerase (DCT) and Pmel17 (SILV, also known as GP100). We used these antibodies to determine the distribution and function of melanosomal proteins in normal human skin (adult and newborn) and in various cutaneous pigmented lesions, such as intradermal nevi, lentigo simplex, solar lentigines and malignant melanomas. We also examined cytokeratin expression in these same samples to assess keratinocyte distribution and function. Immunohistochemical staining reveals distinct patterns of melanocyte distribution and function in normal skin and in various types of cutaneous pigmented lesions. Those differences in the expression patterns of melanocyte markers provide important clues to the roles of melanocytes in normal and in disrupted skin pigmentation. [source] Plasticity of Cadherin,Catenin Expression in the Melanocyte LineagePIGMENT CELL & MELANOMA RESEARCH, Issue 4 2000ALICE JOUNEAU Cadherins are calcium-dependent cell adhesion receptors with strong morphoregulatory functions. To mediate functional adhesion, cadherins must interact with actin cytoskeleton. Catenins are cytoplasmic proteins that mediate the interactions between cadherins and the cytoskeleton. In addition to their role in cell,cell adhesion, catenins also participate in signaling pathways that regulate cell growth and differentiation. Cadherins and catenins appear to be involved in melanocyte development and transformation. Here, we investigated the function of cadherin,catenin complexes in the normal development and transformation of melanocytes by studying the patterns of expression of the cell,cell adhesion molecules, E-, N- and P-cadherin, and the expression of their cytoplasmic partners, ,-, ,- and ,-catenin, during murine development. Similar analyses were performed in vitro using murine melanoblast, melanocyte, and melanoma cell lines in the presence and absence of keratinocytes, the cells with which melanocytes interact in vivo. Overall, the results suggest that the expression of cadherins and catenins is very plastic and depends on their environment as well as the transformation status of the cells. This plasticity is important in fundamental cellular mechanisms associated with normal and pathological ontogenesis, as well as with tumorigenesis. [source] | ||||||||||