Expression of keratin intermediate filament genes in wool follicles of wiltshire sheep

Co-ordinated expression of keratin intermediate filament genes in the wool follicle is essential for the formation of the wool fibre. The expression patterns of three acidic (oKRT31, oKRT35, oKRT38), one neutral-basic (oKRT85) and one acidic inner root sheath keratin (oKRT27) were localised by in situ hybridisation in the wool follicles of Wiltshire sheep. All five genes show distinct expression patterns in the primary wool follicles of the face and lower leg, but have comparable keratinisation zones to their human orthologues. During follicle regression, the expression of these genes is first attenuated distally, gradually becoming restricted to proximal regions before terminating in dormant follicles. The involvement of the expression of oKRT27, oKRT31 and oKRT85, but not oKRT35 and oKRT38, in brush-end formation indicates specialised regulation of keratin expression in the development of this anchoring structure. Intriguingly, significant differences in the expression of cortical oKRT31, oKRT35, oKRT38 and oKRT85 between primary and secondary follicles were identified. The association of asymmetrical expression of some keratins with follicle curvature raises the possibility of a role in fibre crimp formation. Future studies of these and other keratins will generate an understanding of the structural basis of fibre attributes that could contribute to development of novel wool fibres for specific applications.

[1]  P. Schirmacher,et al.  K25 (K25irs1), K26 (K25irs2), K27 (K25irs3), and K28 (K25irs4) represent the type I inner root sheath keratins of the human hair follicle. , 2006, The Journal of investigative dermatology.

[2]  S. Thibaut,et al.  Human hair shape is programmed from the bulb , 2005, The British journal of dermatology.

[3]  L. Alibardi.  Comparative aspects of the inner root sheath in adult and developing hairs of mammals in relation to the evolution of hairs , 2004, Journal of anatomy.

[4]  R. Porter,et al.  Functional analysis of keratin components in the mouse hair follicle inner root sheath , 2004, The British journal of dermatology.

[5]  L Langbein,et al.  The Catalog of Human Hair Keratins , 1999, The Journal of Biological Chemistry.

[6]  E. Fuchs,et al.  A structural scaffolding of intermediate filaments in health and disease. , 1998, Science.

[7]  R. Keough,et al.  Dietary cysteine regulates the levels of mRNAs encoding a family of cysteine-rich proteins of wool. , 1994, The Journal of investigative dermatology.

[8]  M. Raskind,et al.  A method for simultaneous detection of multiple mRNAs using digoxigenin and radioisotopic cRNA probes. , 1993, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[9]  A. Nixon.  A method for determining the activity state of hair follicles. , 1993, Biotechnic & histochemistry : official publication of the Biological Stain Commission.

[10]  G. Rogers,et al.  Analysis of the sheep trichohyalin gene: potential structural and calcium-binding roles of trichohyalin in the hair follicle , 1993, The Journal of cell biology.

[11]  G. Rogers,et al.  Sequence, expression, and evolutionary conservation of a gene encoding a glycine/tyrosine-rich keratin-associated protein of hair. , 1993, The Journal of biological chemistry.

[12]  G. Rogers,et al.  Hair follicle differentiation: expression, structure and evolutionary conservation of the hair type II keratin intermediate filament gene family. , 1992, Development.

[13]  B. Short,et al.  Cell proliferation and cortical cell production in relation to wool growth. , 1979, Australian journal of biological sciences.

[14]  Craven Aj,et al.  Variation of wool characteristics across the body of New Zealand Wiltshire sheep , 2007 .

[15]  H. Winter,et al.  Human hair keratin-associated proteins (KAPs). , 2006, International review of cytology.

[16]  Yu Z-D,et al.  Wool keratins - the challenge ahead , 2006 .

[17]  G. Rogers,et al.  A unique type I keratin intermediate filament gene family is abundantly expressed in the inner root sheaths of sheep and human hair follicles. , 2001, The Journal of investigative dermatology.

[18]  Michael Krawczak,et al.  Human type I hair keratin pseudogene ϕhHaA has functional orthologs in the chimpanzee and gorilla: evidence for recent inactivation of the human gene after the Pan-Homo divergence , 2000, Human Genetics.

[19]  V. Choy,et al.  Inhibitory effect of increased photoperiod on wool follicle growth. , 1996, The Journal of endocrinology.

[20]  A. Nixon,et al.  The microanatomy, cell replication, and keratin gene expression of hair follicles during a photoperiod-induced growth cycle in sheep. , 1995, Acta anatomica.

[21]  R. Morris,et al.  An evaluation of the New Zealand Wiltshire sheep as a model for studies on the physiology of fibre growth , 1991 .

[22]  L. Auber.  VII.—The Anatomy of Follicles Producing Wool-Fibres, with special reference to Keratinization , 1952, Transactions of the Royal Society of Edinburgh.