Single-Nucleus Transcriptional Profiling Revealed Cell Diversity and Albino Mutation Mechanism in the Skin of Channa argus

Body color is the most prominent phenotypic trait in animals. To investigate the molecular regulatory mechanisms underlying skin pigmentation and body color in <i>Channa argus</i>, single-nucleus RNA sequencing technology was employed to analyze cell diversity and functional changes in the skin of normal and albino <i>C. argus</i>. Three pigment-related cell types, seven immune-related cell types, and nine other skin-related structural and functional cell types were identified. The skin of albino <i>C. argus</i>, which appears white to the naked eye, contains numerous melanocytes and iridophores with reflective silver properties. Compared to normal <i>C. argus</i>, melanocytes in albino individuals contained fewer melanin granules, while iridophores exhibited increased chromogenic substances. Melanocyte-specific genes-<i>kitlg</i>, <i>myo5a</i>, and <i>scarb1</i>-were significantly downregulated in albino melanocytes (<i>p</i> < 0.05). Conversely, iridophore-specific genes <i>alk</i>, <i>pnp</i>, and <i>gpnmb</i> were significantly upregulated in albino skin, whereas <i>mlph</i> was significantly downregulated (<i>p</i> < 0.05). Weighted gene co-expression network analysis revealed that <i>scarb1</i> was associated with the melanocyte module, <i>alk</i> was identified as a core gene, and <i>pnp</i> was linked to the iridophore module. Functionally, <i>scarb1</i> is involved in pigment transport, <i>pnp</i> in purine synthesis, and <i>alk</i> is essential for iridophore development. Therefore, <i>scarb1</i>, <i>pnp</i>, and <i>alk</i> may be correlated to albinism in <i>C. argus</i>. Overall, this study constructed a single-cell transcriptional atlas of <i>C. argus</i> skin, providing valuable reference data for further research into the regulatory mechanisms governing body color formation and maintenance in this species.