Genetic and correlative light and electron microscopy evidence for the unique differentiation pathway of erythrophores in brown trout skin

Sušnik Bajec, Simona (author), Djurdjevič, Ida (author), Linares Andújar, Carmen (author), Erdani-Kreft, Mateja (author)

Based on their cell ultrastructure, two types of erythrophores in the spotted skin regions of brown trout (Salmo trutta) were previously described. To test the hypothesis regarding the origin of a new cell type following genome duplication, we analysed the gene and paralogue gene expression patterns of erythrophores in brown trout skin. In addition, the ultrastructure of both erythrophore types was precisely examined using transmission electron microscopy (TEM) and correlative light microscopy and electron microscopy (CLEM). Ultrastructural differences between the sizes of erythrophore inclusions were confirmed; however, the overlapping inclusion sizes blur the distinction between erythrophore types, which we have instead defined as cell subtypes. Nevertheless, the red spots of brown trout skin with subtype 2 erythrophores, exhibited unique gene expression patterns. Many of the upregulated genes are involved in melanogenesis or xanthophore differentiation. In addition, sox10, related to progenitor cells, was also upregulated in the red spots. The expressions of paralogues derived from two genome duplication events were also analysed. Multiple paralogues were overexpressed in the red spots compared with other skin regions, suggesting that the duplicated gene copies adopted new functions and contributed to the origin of a new cell subtype that is characteristic for red spot. Possible mechanisms regarding erythrophore origin are proposed and discussed. To the best of our knowledge, this is the first study to evaluate pigment cell types in the black and red spots of brown trout skin using the advanced CLEM approach together with gene expression profiling.

• Language: English
• Keywords: development, gene expression profiling, molecular evolution, single-cell imaging, super-resolution microscopy, zoology
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 15 str.
• Numbering: Vol. 12, art. 1015
• PID: 20.500.12556/RUL-145261
• UDC: 597.2/.5
• ISSN on article: 2045-2322
• DOI: 10.1038/s41598-022-04799-7
• COBISS.SI-ID: 94290179
• Publication date in RUL: 14.04.2023

Record is a part of a journal

• Title: Scientific reports
• Shortened title: Sci. rep.
• Publisher: Nature Publishing Group
• ISSN: 2045-2322
• COBISS.SI-ID: 18727432

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: genetika, ribe, potočna postrv, pigmentacija kože