Transcriptomic analysis of mouse embryonic skin cells reveals previously unreported genes expressed in melanoblasts.

Studying the development of melanoblasts, precursors of melanocytes, is challenging owing to their scarcity and dispersion in the skin embryo. However, this is an important subject because diverse diseases are associated with defective melanoblast development. Consequently, characterizing patterns of expression in melanoblasts during normal development is an important issue. This requires isolating enough melanoblasts during embryonic development to obtain sufficient RNA to study their transcriptome. ZEG reporter mouse line crossed with Tyr::Cre mouse line was used to label melanoblasts by enhanced green fluorescent protein (EGFP) autofluorescence. We isolated melanoblasts by FACS from the skin of E14.5-E16.5 embryos, and obtained sufficient cells for large-scale transcriptomic analysis after RNA isolation and amplification. We confirmed our array-based data for various genes of interest by standard quantitative real-time RT-PCR. We demonstrated that phosphatase and tensin homolog was expressed in melanoblasts but BRN2 was not, although both are involved in melanomagenesis. We also revealed the potential contribution of genes not previously implicated in any function in melanocytes or even in neural crest derivatives. Finally, the Schwann cell markers, PLP1 and FABP7, were significantly expressed in melanoblasts, melanocytes, and melanoma. This study demonstrates the feasibility of the transcriptomic analysis of purified melanoblasts at different embryonic stages and reveals the involvement of previously unreported genes in melanoblast development.