Conflicts of interest: None.
Immunocytochemistry suggests that the prevalence of a sub-type of beta-proteins determines the hardness in the epidermis of the hard-shelled turtle
Article first published online: 19 NOV 2013
© 2013 Wiley Periodicals, Inc.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
Volume 322, Issue 1, pages 54–63, January 2014
How to Cite
2014. Immunocytochemistry suggests that the prevalence of a sub-type of beta-proteins determines the hardness in the epidermis of the hard-shelled turtle. J. Exp. Zool. (Mol. Dev. Evol.) 322B:54–63..
- Issue published online: 9 DEC 2013
- Article first published online: 19 NOV 2013
- Manuscript Accepted: 11 OCT 2013
- Manuscript Revised: 5 OCT 2013
- Manuscript Received: 6 JUL 2013
- Comparative Histolab
- University of Bologna. Grant Number: RFO 2010
The corneous layer of the epidermis in hard-shelled turtles largely derives from the accumulation of beta-proteins as indicated by microscopic, in situ hybridization, and immunocytochemical and Western blotting analysis. The expression of mRNAs of one of the most common type of beta-proteins shows higher expression in upper spinosus and pre-corneous keratinocytes of growing scutes. Two beta-proteins of 14–16 kDa, indicated as Tu2 and Tu17 and representing two subtypes of beta-proteins co-accumulate in the thick corneous layer of the epidermis in hard-shelled turtle. The two beta-proteins apparently mix in differentiating and mature corneocytes although Tu2 appears more prevalent than Tu17. The specific role of the different subtypes in the formation of the hard corneous material of the carapace and plastron is not clear. It is hypothesized that the relative amount of beta-proteins belonging to the two subclasses in relation to the alpha-keratin meshwork present in keratinocytes contributes to the formation of a variably resistant and inflexible corneous layer. Tu17 may have a more globular structure than Tu2 and is likely present in denser areas of the corneous layer containing also alpha-keratin. The increase of cysteine–glycine-rich beta-proteins in the matrix located among alpha-keratin filaments may allow the formation of a hard corneous material, probably through increase of cross-bridge formation and hydrophobicity. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 54–63, 2014. © 2013 Wiley Periodicals, Inc.