Tex19, a Mammalian Specific Protein, With a Restricted Expression in Pluripotent Stem Cells and Germ Line

¹ IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Department of developmental biology and Bioinformatics platform of Strasbourg, Illkirch, F-67400 France; Inserm, U596, Illkirch, F-67400 France; CNRS, UMR7104, Illkirch, F-67400 France; Université Louis Pasteur, Faculté de Médecine, Centre Hospitalier Universitaire ; Strasbourg, F-67000 France.
² IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Department of developmental biology and Bioinformatics platform of Strasbourg, Illkirch, F-67400 France; Inserm, U596, Illkirch, F-67400 France; CNRS, UMR7104, Illkirch, F-67400 France; Université Louis Pasteur, Faculté de Médecine, Centre Hospitalier Universitaire ; Strasbourg, F-67000 France. Département de Pharmacologie et Physicochimie, UMR 7175, CNRS Université Louis Pasteur Strasbourg, Illkirch, France.

^* To whom correspondence should be addressed. E-mail: viville{at}igbmc.u-strasbg.fr.

	Abstract

Although ES cells properties make them very attractive in the field of replacement therapy, the molecular mechanisms involved in the maintenance of their pluripotency is not fully characterised. Starting from the observation that most pluripotent markers are also expressed by spermatogonia stem cells, we identified Tex19 as a new potential pluripotency marker. We show that Tex19 is a mammalian specific protein duplicated in mouse and rat, renamed Tex19.1 and Tex19.2, whereas only one form is found in human. In mouse, both forms are localised on chromosome 11 and transcribed in opposite direction. Tex19 proteins are well conserved, showing two highly conserved domains that do not present any similarity with any other known domains. We show that Tex19.2 is specifically detected in the male somatic gonad lineage whereas, Tex19.1 expression is very similar to Oct4. Transcripts are maternally inherited and expression starts as soon as the early embryo and later is limited to the germ line. Tex19.1 transcripts are also detected in mouse pluripotent stem cells and its expression, as for Oct4, decreases after murine embryonic stem and germ cell differentiation. Human TEX19 is more closely related to murine Tex19.1 and was also detected in adult testis and in undifferentiated ES cells. By immunofluorescence, we found that Tex19.1 protein localizes to the nucleus of mouse ES and ICM cells. All of these results suggest that Tex19.1, as well as human TEX19, could be a new factor involved in the maintenance of self-renewal or pluripotency of stem cells.