P3.29 CYSTEINE-RICH INTESTINAL PROTEINS ARE DIFFENTIALLY EXPRESSED IN HAIR FOLLICLES.

Steven W Gordon¹, Marianne S Elston², Zhidong Yu¹, Allan J Nixon¹, Anthony J Craven¹, Allan J Pearson¹, John V Conaglen²

¹AgResearch, Hamilton, New Zealand. ²Waikato Clinical School, University of Auckland, Hamilton, New Zealand

Ferret skin cDNA was screened by differential display for candidate genes involved in the control of hair growth. One of the identified expressed sequence tags showed homology to human cysteine-rich intestinal proteins 1 and -2 (CRIP1 and -2). CRIP proteins belong to Group 2 of the LIM domain family and are highly conserved amongst different species. CRIP1 is developmentally regulated and glucocorticoid-responsive in the intestine of rats, and appears to have an immune function whereby it favours Th2 cytokine expression. CRIP2 has been localized to the actin-rich structures in the cell cortex and is regulated by oestrogen, which can be a potent inhibitor of hair growth. However, the involvement of CRIP1 and -2 in hair growth has not been investigated.

We performed Northern blot analysis and in situ hybridisation of CRIP gene expression in ferret skin across the hair cycle using the cloned cDNA to generate DNA and RNA probes. Two transcripts corresponding to CRIP1 and -2 were identified at approximately 600 and 2400 bp. The smaller transcript (putatively CRIP1) showed decreased expression in late anagen compared with the other stages, while the larger transcript (putatively CRIP2) was present only in skin samples with telogen and early proanagen ferret hair follicles. In situ hybridization in ferret skin demonstrated cytoplasmic localization of CRIP mRNA in the epidermis, as well as the outer root sheath, germinal matrix and cortex of hair follicles. Interestingly, expression of CRIP1 and/or CRIP2 appears to be associated with the growth and differentiation stages of hair follicle cells.  As both genes are responsive to hormones that influence growth of hair, CRIP1 and CRIP2 are potential mediators of hormonal effects on hair follicles.