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Normal pigment production
Author(s) -
ARVEILER B
Publication year - 2014
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2014.2661.x
Subject(s) - melanosome , melanin , neural crest , melanocyte , microbiology and biotechnology , biology , tyrosinase , microphthalmia associated transcription factor , chromatophore , neuroepithelial cell , retinal pigment epithelium , anatomy , retinal , botany , melanoma , stem cell , biochemistry , genetics , embryo , neural stem cell , enzyme
Melanin is synthesized in melanocytes and retinal pigment epithelial cells. Two main types of melanin are produced: eumelanin (brown, black) and phaeomelanin (yellow, orange). Pigmentation is a complex process involving various steps from normal development of melanocytes to the synthesis of melanin itself. In the skin and choroid, precursors of melanocytes are melanoblasts which are derived from the neural crest. Retinal pigment epithelium cells are generated directly from the optic neuroepithelium. Melanoblasts migrate and colonize the epidermis, hair follicles, and ocular, ear and nervous structures. The differentiation of melanoblasts into melanocytes is controlled by numerous transcription factors and signalling pathways, and is characterized by the acquisition of Tyrosinase activity, the presence of mature melanosomes, and the formation of dendrites. Melanin production results from catalytic activities by Tyrosinase, TRP‐1 and TRP‐2 and occurs in melanosomes which follow a maturation process involving four stages (I – IV). Melanosomes are transported from the perinuclear region to the end of melanocytic dentrites, where they are eventually transferred to keratinocytes.