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Epidermal threads reveal the origin of hagfish slime

Authors :
Yu Zeng
David C Plachetzki
Kristen Nieders
Hannah Campbell
Marissa Cartee
M Sabrina Pankey
Kennedy Guillen
Douglas Fudge
Source :
eLife, Vol 12 (2023)
Publication Year :
2023
Publisher :
eLife Sciences Publications Ltd, 2023.

Abstract

When attacked, hagfishes produce a soft, fibrous defensive slime within a fraction of a second by ejecting mucus and threads into seawater. The rapid setup and remarkable expansion of the slime make it a highly effective and unique form of defense. How this biomaterial evolved is unknown, although circumstantial evidence points to the epidermis as the origin of the thread- and mucus-producing cells in the slime glands. Here, we describe large intracellular threads within a putatively homologous cell type from hagfish epidermis. These epidermal threads averaged ~2 mm in length and ~0.5 μm in diameter. The entire hagfish body is covered by a dense layer of epidermal thread cells, with each square millimeter of skin storing a total of ~96 cm threads. Experimentally induced damage to a hagfish’s skin caused the release of threads, which together with mucus, formed an adhesive epidermal slime that is more fibrous and less dilute than the defensive slime. Transcriptome analysis further suggests that epidermal threads are ancestral to the slime threads, with duplication and diversification of thread genes occurring in parallel with the evolution of slime glands. Our results support an epidermal origin of hagfish slime, which may have been driven by selection for stronger and more voluminous slime.

Details

Language :
English
ISSN :
2050084X
Volume :
12
Database :
Directory of Open Access Journals
Journal :
eLife
Publication Type :
Academic Journal
Accession number :
edsdoj.0c2f62efd5d14075af47c639c0b3a3f4
Document Type :
article
Full Text :
https://doi.org/10.7554/eLife.81405