The proteomics of wool fibre morphogenesis

Area of Science:

• Wool follicle biology
• Proteomics
• Hair fiber development

Background:

• Understanding wool fiber formation requires detailed knowledge of protein expression within the follicle.
• Previous studies relied on gene expression and indirect methods to infer protein presence.

Purpose of the Study:

• To directly identify and localize proteins within distinct wool follicle portions using gel and gel-free proteomic techniques.
• To correlate protein expression patterns with morphological changes during wool fiber development.

Main Methods:

• Dissection of individual wool follicles into four distinct portions: bulb, elongation, keratogenous, and keratinisation zones.
• Gel-free proteomic analysis of 30 dissected follicle samples.
• Two-dimensional gel electrophoresis (2DE) analysis of 50 dissected follicle samples.

Main Results:

• Identified the early appearance of keratins K31, K35, K85, epithelial keratin-associated protein (KAP) trichohyalin in the bulb, and cortical KAP KAP11.1 in the elongation portion.
• Observed the progressive appearance of other major trichocyte keratins and cortical KAPs in higher follicle zones, consistent with gene expression data and morphology.
• Detected proteins including desmoplakin, vimentin, epithelial keratins, histones, ribosomal proteins, and collagens.
• 2DE analysis revealed significant modifications in trichocyte keratins during keratinisation and identified epithelial keratins and dermal components.

Conclusions:

• Proteomic analysis provides direct evidence of protein localization and changes during wool follicle development.
• The observed protein expression patterns align with known gene expression and morphological changes, enhancing our understanding of wool fiber formation.
• Keratinisation involves substantial modifications of trichocyte keratins, as indicated by 2DE analysis.