Phenotype Image Detail

Image

Caption

Melanocyte specific PIKfyve knockout mice exhibit abnormal melanocyte morphology and trafficking. (A) 4mm biopsies were obtained from Pikfyve^tm2.1Tssk/Pikfyve^tm2.1Tssk Tg(Tyr-cre/ERT2)13Bos/0 mice and processed for electron microscopy. (a) Anagen hair bulbs contained melanocytes in various conditions, i.e. normal (N), abnormal (Ab), and intermediate (I). (b) Approximately 40% appeared morphologically normal resembling follicular melanocytes in C57BL mice (N). (d) Another 40% exhibited profound vacuolization exhibiting vesicles within vacuoles resembling multivesicular bodies (inset to d) with very few if any melanosomes. (c) Occasionally, approximately 20% melanocytes relatively fewer melanosomes generally of earlier stages than the morphologically normal melanocytes. BARS: a = 10 microns, b, c & d = 3.0 microns, inset to d = 0.75 microns. (B) 4mm biopsies were obtained from mutant mice and processed for DOPA histochemistry and electron microscopy. (a) morphologically normal melanocytes exhibited minimal DOPA reaction product in the trans Golgi network and associated 50 nm vesicles (arrows). (b) Intermediate melanocyte exhibited uncharacteristic DOPA reaction product that was clustered in large vacuoles some of which contained filamentous material (arrows). (c) The vacuoles of abnormal melanocytes exhibited very little DOPA reaction product with an occasional deposition around vesicles within the vacuoles (arrow) and attached to the limiting membrane of the vacuole (arrow with asterisk). BARS: a, b & c = 1.0 microns, d = 0.3 microns. (C) Ultrastructure of melanocytes cultured from mutant mice recapitulate the aberrant morphology observed in hair bulb melanocytes from mutant mice. a & b) A prominent number of cultured melanocytes exhibited vacuoles with a central core of amorphorus material (arrows) with occasional stage IV melansomes (arrowheads). c & d) A significant number of melanocytes exhibited many stage IV melanosomes (arrowheads) and earlier stage melanosomes with normally arraigned melanofilaments (arrowheads with asterisks) as well as few vacuoles with a central core of amorphorus material (arrows). N = nucleus. Bars: a-d = 5 microns, insets = 2 microns.

Copyright

This image is from Liggins MC, PLoS Genet 2018 Mar;14(3):e1007290, and is displayed under the terms of the Creative Commons Attribution 4.0 International License. J:262141

Associated Alleles

Symbol	Name
Pikfyve^tm2.1Tssk	phosphoinositide kinase, FYVE type zinc finger containing; targeted mutation 2.1, Takehiko Sasaki
Tg(Tyr-cre/ERT2)13Bos	transgene insertion 13, Marcus Bosenberg

Associated Genotypes

Allelic Composition	Genetic Background
Pikfyve^tm2.1Tssk/Pikfyve^tm2.1Tssk Tg(Tyr-cre/ERT2)13Bos/0	involves: C57BL/6 * C57BL/6J