Potential role of Nanos3 in maintaining the undifferentiated spermatogonia population.
Nanos gene encodes for zinc-finger protein with putative RNA-binding activity which shows an evolutionary conserved function in germ cell development. In the mouse, three Nanos homologs have been identified: Nanos1, Nanos2 and Nanos3. The Nanos3 ortholog is expressed in both male and female gonads of early embryo and, after birth, it is found only in the testis. Nanos3 targeted disruption results in the complete loss of germ cells in both sexes; however the role of Nanos3 in the testis during the postnatal period has not been explored yet. In this study, we show that, in prepuberal testis, Nanos3 is expressed in undifferentiated spermatogonia and that its up-regulation causes accumulation of cells in the G1 phase, indicating that this protein is able to delay the cell cycle progression of spermatogonial cells. This is in line with the observation that the cell cycle length of the undifferentiated germ cells is longer than in differentiating spermatogonia. We also demonstrate a conserved mechanism of action of Nanos3, involving the interaction with the murine RNA-binding protein Pumilio2 and consisting of a potential translational repressor activity. According to the possible role of Nanos3 in inhibiting spermatogonia cell differentiation, we show that treatment with the differentiating factor all-trans retinoic acid induces a dramatic down-regulation of its expression. These results allow to conclude that, in the prepuberal testis, Nanos3 is important to maintain undifferentiated spermatogonia via the regulation of their cell cycle.
Lolicato
Francesca
F
Department of Public Health and Cell Biology, University of Rome Tor Vergata, Via Montpellier, 1, 00133, Rome, Italy.
Marino
Rita
R
Paronetto
Maria Paola
MP
Pellegrini
Manuela
M
Dolci
Susanna
S
Geremia
Raffaele
R
Grimaldi
Paola
P
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D004622:Embryo, Mammalian; D004926:Escherichia coli / Q000235:genetics; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D018189:Immunomagnetic Separation; D017403:In Situ Hybridization; D007668:Kidney / Q000166:cytology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D016366:Open Reading Frames; D010957:Plasmids; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D013091:Spermatogenesis; D013093:Spermatogonia / Q000166:cytology / Q000502:physiology*; D013737:Testis / Q000033:anatomy & histology / Q000166:cytology / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
C113027:Bcl6b protein, mouse; D018076:DNA, Complementary; C477342:Nanos3 protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; C445087:Pum2 protein, mouse; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D049452:Green Fluorescent Proteins; D014212:Tretinoin; D005982:Glutathione Transferase