POF1B protein distribution in normal and pathological skin

In this study a rabbit polyclonal antibody anti human POF1B, raised against the corresponding fusion protein, was used to characterize on frozen sections the tissue distribution of the protein in normal and pathological skin conditions in which there are alterations of epidermal intercellular junctions (such as psoriasis, ichthyosis, non melanoma skin cancers, pemphigus, pemphigoid, Hailey-Hailey disease). POF1B is a candidate gene for premature ovarian failure mapping to the Xq21 region. Mattison et al. [Am J Hum Genet, 1984] proposed that POF may be a Mendelian disorder, inherited paternally or maternally as an autosomal or X-linked dominant manner. Very little is known about the function of the gene, but its expression before the generation of the epidermal permeability barrier and its localisation to the junctional domain of epithelial tissues have led to the hypothesis that POF1B plays a role in epithelial polarity. Significant homology to barmotin/7H6, a tight junction associated protein, and to the myosin heavy chain rod domain have been demonstrated. The defects were associated with altered ciliogenesis and cystogenesis. In normal skin POF1B molecules are exclusively localized at granular layers showing both a cytoplasmic and membrane distribution. In icthyosis the granular layers are increased and POF1B are mainly localized in perinuclear area, while in hyperproliferative psoriatic epidermis the POF1B staining shows a membrane localization. Altered expression of POF1B, showing perinuclear intracellular distribution, was clearly demonstrated in squamous cell carcinomas and in acantholytic areas of cases of pemphigus and HaileyHailey disease. Our data confirme an important role of this molecule for the acquisition and maintenance of the polarised phenotype in pluri-stratified normal and pathological epidermis.