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Updated: Apr 16, 2026
Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells
Published on: March 3, 2016
Conditional Deletion of Kit in Melanocytes: White Spotting Phenotype Is Cell Autonomous
Hitomi Aoki1, Hiroyuki Tomita2, Akira Hara2
1Department of Tissue and Organ Development, Gifu University Graduate School of Medicine, Gifu, Japan.
Abstract:
It is well established that cell-intrinsic signaling through the receptor tyrosine kinase KIT is critical for the development of neural crest-derived melanocytes. Nevertheless, it is not entirely clear whether Kit acts exclusively in a melanocyte-autonomous manner or in addition indirectly through other cell types. To address this question in vivo, we generated a targeted allele of Kit that allowed for CRE recombinase-mediated deletion of the transmembrane domain of KIT. Mice carrying one copy of the targeted allele and expressing CRE under the melanoblast/melanocyte-specific tyrosinase promoter exhibited a white spotting phenotype that was even more extensive compared with that found in mice heterozygous for a Kit-null allele. This phenotype is unlikely the result of sequestration of KIT ligand by neighboring cells or by potentially secreted forms of KIT because the spotting phenotype could not be rescued by overexpression of KITL. Likewise, overexpression of endothelin-3 or hepatocyte growth factor was unable to rescue melanocytes in these mice. Although the severity of the observed phenotype remains to be explained, the findings indicate that melanocyte-selective impairment of Kit is sufficient to interfere with normal melanocyte development.
Insights
The receptor tyrosine kinase KIT is crucial for melanocyte development. Impairing KIT signaling specifically within melanocytes is sufficient to disrupt their development, indicating a cell-autonomous role.
Area of Science:
- Developmental Biology
- Cell Signaling
- Genetics
Background:
- Receptor tyrosine kinase KIT signaling is essential for neural crest-derived melanocyte development.
- The precise role of KIT in melanocyte development (autonomous vs. indirect effects) requires further investigation.
Purpose of the Study:
- To investigate the in vivo role of KIT signaling in melanocyte development.
- To determine if KIT acts exclusively within melanocytes or also influences them indirectly.
Main Methods:
- Generation of a targeted Kit allele for CRE recombinase-mediated deletion of the KIT transmembrane domain.
- Utilized a melanoblast/melanocyte-specific tyrosinase promoter driving CRE expression in mice.
- Phenotypic analysis of resulting mouse models, including comparison with Kit-null heterozygotes.
Main Results:
- Mice with melanocyte-specific Kit impairment exhibited an extensive white spotting phenotype, more severe than Kit-null heterozygotes.
- Overexpression of KIT ligand (KITL), endothelin-3, or hepatocyte growth factor did not rescue the observed phenotype.
- The findings suggest KIT acts autonomously within melanocytes.
Conclusions:
- Melanocyte-selective impairment of KIT signaling is sufficient to disrupt normal melanocyte development.
- The study provides evidence for a cell-autonomous function of KIT in melanocyte development.
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