Genetics of pigment cells: lessons from the tyrosinase gene family

ISREC (Swiss Institute for Experimental Cancer Research), National Center of Competence in Research Molecular Oncology, Epalinges, Switzerland.
Histology and histopathology (Impact Factor: 2.24). 06/2006; 21(5):567-78.
Source: PubMed

ABSTRACT In mammals, the melanin pigment is produced in two cell types of distinct developmental origins. The melanocytes of the skin originate form the neural crest whereas the retinal pigment epithelium (RPE) of the eye originates from the optic cup. The genetic programs governing these two cell types are thus quite different but have evolved to allow the expression of pigment cell-specific genes such as the three members of the tyrosinase-related family. Tyrosinase, Tyrp1 and Dct promoters contain a motif termed E-box which is bound by the transcription factor Mitf. These E-boxes are also found in the promoters of the corresponding fish genes, thus highlighting the pivotal role of Mitf in pigment cell-specific gene regulation. Mitf, which displays cell type-specific isoforms, transactivates the promoters of the tyrosinase gene family in both pigment cell lineages. However, specific DNA motifs have been found in these promoters, and they correspond to binding sites for RPE-specific factors such as Otx2 or for melanocyte-specific factors such as Sox10 or Pax3. The regulation of pigment cell-specific expression is also controlled by genetic elements located outside of the promoter, such as the tyrosinase distal regulatory element located at -15 kb which acts as a melanocyte-specific enhancer but also protects from spreading of condensed chromatin. Thus, by using the tyrosinase gene family as a model, it is possible to define the transcription factor networks that govern pigment production in either melanocytes or RPE.

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    • "Interestingl y, the similar expression profile was also observed for the prophenolo xidase (proPO) in crayfish brain. The Tyr is present in pigment cells from two different developmental origins and they are melanocytes /melanophores which originate from neural crest, and the retinal pigment epithelium (RPE) with an optic cup origin (developing forebrain) (Murisier and Beermann, 2006 ). The function of the Tyr in the RPE has been suggested to be important for bright light adaptation in the zebrafish and is involved in the production of L-DOPA and dopamine neurotransm itter (Page-McCaw et al., 2004 ). "
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    ABSTRACT: Circadian clock is important to living organisms to adjust to the external environment. This clock has been extensively studied in mammals, and prokineticin 2 (Prok2) acts as one of the messenger between the central nervous system and peripheral tissues. In this study, expression profiles of Prok1 and Prok2 were investigated in a non-mammalian vertebrate brain, zebrafish, and the expression was compared to the Prok homologues, astakines (Ast1 and Ast2) in crayfish. These transcripts exhibited circadian oscillation in the brain, and Ast1 had similar pattern to Prok2. In addition, the expression of tyrosinase, an enzyme which expression is regulated by E-box elements like in Prok2, was also examined in zebrafish brain and was compared with the expression of prophenoloxidase (proPO), the melanization enzyme, in crayfish brain. Interestingly, the expressions of both Tyr and proPO displayed circadian rhythm in a similar pattern to Prok2 and Ast1, respectively. Therefore, this study shows that circadian oscillation of prokineticin homologues and enzymes involved in melanization are conserved.
    Developmental and comparative immunology 03/2013; 40(2). DOI:10.1016/j.dci.2013.03.002 · 3.71 Impact Factor
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    • "Genomic sequence details are available from: http:// db¼gene&cmd¼Retrieve&dopt¼full_report&list_uids¼7306 The control of TYRP1 gene expression is achieved through regulatory elements also at the TYRP1 locus (Review by Murisier and Beermann, 2006). "
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    ABSTRACT: Melanoma prognosis is based on specific pathological features at the primary lesion. In metastatic patients, the extent of lymph node involvement is also an important prognosis indicator. Many progression markers both in tissues and serum, including circulating tumor cells, have been studied and new molecular markers are awaited from high-throughput screenings to discriminate between clinical stages and predict disease progression. The present review focuses on human tyrosinase related protein 1 also known as gp75 glycoprotein (Tyrp1/gp75), a melanosomal protein involved in the pigmentary machinery of the melanocyte and often used as differentiation marker, with a special emphasis on its emerging roles in the malignant melanocyte and melanoma progression.
    Molecular oncology 02/2011; 5(2):150-5. DOI:10.1016/j.molonc.2011.01.006 · 5.94 Impact Factor
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    • "Homozygous-mutant Mitf mice show severe defects of body pigmentation, have small unpigmented eyes, lack melanocytes in the inner ear and are deaf (reviewed in Steingrimsson et al. 2004). Genetic experiments have shown that multiple isoforms of Mitf are responsible for driving the expression of Tyr and Tyrp in melanocytes and retinal pigmented epithelium in cooperation with Otx and Pax genes (Martinez-Morales et al. 2004; Murisier & Beermann 2006; Bharti et al. 2008). Besides its role in melanogenesis , Mitf has been suggested to be involved in the regulation of the pteridine synthesis pathway in zebrafish (Ziegler 2003). "
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    ABSTRACT: Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components-photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, Galpha protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.
    Philosophical Transactions of The Royal Society B Biological Sciences 11/2009; 364(1531):2819-32. DOI:10.1098/rstb.2009.0079 · 6.31 Impact Factor
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