Details

Autor(en) / Beteiligte

• Jimbow, Kowichi
• Szabo, George
• Fitzpatrick, Thomas B.

Titel

Ultrastructural investigation of autophagocytosis of melanosomes and programmed death of melanocytes in White Leghorn feathers: a study of morphogenetic events leading to hypomelanosis

Ist Teil von

• Developmental biology, 1974, Vol.36 (1), p.8-23

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1974

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• White Leghorn chickens have decreased feather melanin, not because pigment cells are absent, but because of a genetically determined programmed cell death that causes pigment cells to degenerate prematurely before the melanin can be deposited in the feathers. In this paper, we studied the feather germs of this breed and of control Black Minorca chickens by light and electron microscopy to elucidate further the mechanism of cell death. White Leghorn feature-germ melanocytes produced a large number of unmelanized melanosomes which, however, did not become melanized, nor were they transferred into the keratinocytes of the follicles. From day 10 of incubation onward, large autophagosomes appeared in the melanocytes of White Leghorn feather follicles. These autophagosomes were acid phosphatase positive and engulfed incompletely melanized melanosomes. They also contained melanosome degradation products. Finally, degeneration of the whole melanocyte followed. These necrotic melanocytes were engulfed by normal-looking keratinocytes of the same follicle. In Black Minorcas, on the other hand, there was a normal sequence of synthesis, melanization, and transfer of melanosomes. The melanocytes degenerated only at the time of hatching, without the formation of large autophagosomes.