Melanogenesis is the unique process of producing the melanin within
melanosomes and is a major function of both differentiated normal melanocytes and malignant melanoma cells [23].
The skin contains ABC transporters, responsible for molecular transportation across cell membranes, which play roles in
melanosome transport to surrounding keratinocytes [33].
Since norepinephrine (NE) could induced
melanosome aggregation in fish scales [11,12,30], parallel treatment with NE was used as a positive control for pigment aggregation.
Theconstitutive skin pigmentation is regulated by a number of factors including the relative amounts of eumelanin (brown- black pigment) and pheomelanin (red-yellow pigment) synthesized within
melanosomes melanocyte dendricity transport of
melanosomes to dendrites and the rate of
melanosome transfer to the surrounding keratinocytes (Abdel-Malek and Kadekaro2006).It is also reported that autophagy plays a role in skin colour in humans by regulating
melanosome degradation in keratinocytes and thereby contributes to the ethnic diversity of skin color (Murase et al.
The evolution of diverse
melanosomes in these organisms raises the possibility that
melanosome shape and size could yield insights into dinosaur physiology.
This phenomenon, referred to as "
melanosome hijacking", has already been described for varicella-zoster virus, another herpesvirus that displays tropism for human skin [78].
Melanin fills the
melanosome, which is transported to the dendrites of the melanocyte and is eventually transferred to the keratinocytes where it forms a nuclear cap that protects DNA from UV-induced damage.
(4) Diagnosis can be made if the lesion is positive for antigens of
melanosome, such as protein S-100 and HMB45.
Moreover, autophagy activation promotes
melanosome degradation in keratinocytes.
Iris pigment dispersion and associated atrophy have also been observed in several other mouse models and causative genes together implicate
melanosome genes as playing a central role in iris pigment dispersion pathogenesis [77, 82-84].
That's when Vinther and colleagues proposed that microscopic structures in a roughly 125-million-year-old fossil feather were actually a type of
melanosome (SN: 8/2/08, p.10).
The antibodies tested were vimentin (dilution 1: 100); [alpha]-SMA (dilution 1: 200); desmin (dilution 1:100); myogenin (dilution 1:100); S-100 protein (dilution 1: 500); CD99 (dilution 1: 100); CD34 (dilution 1: 50); B-cell lymphoma 2 (Bcl-2) protein (dilution 1:100); CD10 (dilution 1: 200); CD117 (dilution 1: 400); cytokeratins (AE1/AE3 clone; dilution 1:50); epithelial membrane antigen (EMA) (dilution 1 : 100); anti-human
melanosome (HMB45) (dilution 1: 300), all from Dako, Glostrup, Denmark.
