Reg I protein in healthy and seminoma human testis
V. Mauro1, D. Carette1, D. Chevallier1, J.F. Michiels2, D. Segretain1, G. Pointis1 and F. Sénégas-Balas1
1INSERM, U895, C3M, University of Nice-Sophia-Antipolis, UFR Medecine and 2Department of Anatomy and Pathology, CHU, F-06002 Nice, France.
Offprint requests to: F. Sénégas-Balas: INSERM, U895, Centre Méditerranéen Moléculaire (C3M), Physiopathologie du contrôle de la prolifération germinale: mécanismes génomiques et non génomiques, Nice, F-06204 Cedex 3, France. e-mail: senegas@unice.fr
Summary. Regenerating gene (Reg), encodes a secretory protein with growth and differentiation stimulating effects mostly in digestive tissues. Overexpression of Reg proteins and specifically of Reg I, one member of the Reg family, is associated with several human diseases and cancers. In the present study we analyzed the expression of Reg I in normal rodent and human testes where germ cells normally proliferate and differentiate into spermatozoa, and in seminoma testis, the most common cancer of young men. Western blot analyses demonstrated the presence of a specific band at 19 kDa in human and rodent testis extracts. Immunofluorescence and deconvolution microscopy demonstrated that Reg I was present within the seminiferous tubules in both Sertoli and germ cells. By using a Sertoli cell line we demonstrated that Reg I was localized at the plasma membrane even in the absence of contact between neighboring cells and appeared before the tight junction associated protein ZO-1 was revealed at this location. Reg I was strongly expressed in human seminoma testis tissue and in a human tumor germ cell line where the immunoreactive signal was mainly detected at the plasma membrane level. These data showing for the first time the weak presence of Reg I in the normal testis and its strong expression in the testis cancer suggest a potential role of Reg I in normal and neoplastic germ cell proliferation. Histol Histopathol 23, 1195-1203 (2008)
Key words: Reg I, Testis, Seminoma
DOI: 10.14670/HH-23.1195