What are Melanoblast cells?
2.1. Melanoblasts are neural crest–derived specific precursors of melanocytes that are unable to synthesize melanin because of the absence of tyrosinase (TYR)-related protein. Melanocytes of the epidermis and the hair bulb develop separately and are distinct cell populations.
What is the function of a melanocyte?
Melanocytes are cells of neural crest origin. In the human epidermis, they form a close association with keratinocytes via their dendrites. Melanocytes are well known for their role in skin pigmentation, and their ability to produce and distribute melanin has been studied extensively.
What is the function of Melanoblasts?
Melanoblasts (MB) are the embryonic precursors of pigment-producing melanocytes present in the eyes, ears, meninges, heart, and skin. They are thought to arise directly from neural crest cells (NCC) and/or secondarily from other NCC-derived cells, Schwann cell precursors (SCP).
Is melanin a protein?
Melanin is a complex polymer derived from the amino acid tyrosine. Melanin is responsible for determining skin and hair colour and is present in the skin to varying degrees, depending on how much a population has been exposed to the sun historically.
What is the Melanogenesis process?
Melanogenesis is the complex process by which the pigment melanin is produced in melanosomes by melanocytes. There are two distinct types of melanin: black to brown eumelanin and yellow to reddish-brown pheomelanin. The ratio of eumelanin to pheomelanin determines the color of the hair, skin, and eyes.
How does the melanocyte cell work?
Melanocyte is a highly differentiated cell that produces a pigment melanin inside melanosomes. This cell is dark and dendritic in shape. Melanin production is the basic function of melanocyte. With the process of differentiation this cell loses the proliferative potential.
What is the function of melanocytes quizlet?
Melanocytes produce and secrete melanin. Melanin synthesis occurs in melanosomes. Melanosomes are transferred to keratinocytes and cap the keratinocyte nucleus protecting it from UV damage.
What is the difference between melanocytes and melanosomes?
Melanocytes produce specific organelles, termed melanosomes, in which melanin pigment is synthesized and deposited. In the skin, melanosomes are transferred from melanocytes to neighboring keratinocytes in order to form perinuclear melanin caps (Hearing, 2005).
What is the role of tyrosinase?
Tyrosinase is responsible for the first step in melanin production. It converts a protein building block (amino acid) called tyrosine to another compound called dopaquinone.
What is the role of MITF in melanoblast differentiation?
Melanoblast differentiation in the skin, characterized by melanization and the acquisition of a dendritic phenotype, relies heavily on MITF, whose targets include many of the genes involved in melanin biosynthesis (such as the previously mentioned Dct, tyrosinase-related protein-1, and tyrosinase).
Can a melanoblast be derived from a fibroblast?
Melanoblast-like cells can also be derived from melanocytes under specific culture conditions including low calcium and supplementation with stem cell factor, fibroblast growth factor (FGF)-2 and endothelin 3, but whether this is a significant mechanism for melanoblast production in vivo remains uncertain. 41
How can melanoblasts be enriched from human skin?
Melanoblasts can be enriched from adult human skin by the use of marker selection including KIT (CD117) and dopachrome tautomerase and more recently by calcium pulse isolation from keratinocyte culture. 39
How does a kit mutation affect a melanoblast?
Mutations in KIT or KITL lead to the formation of white coat, as KIT and KITL are involved in the survival and migration of melanoblasts. Mutations in KIT affect the development of melanocytes derived from the neural crest cells but not those derived from the central nervous system.