The continuation of the spermatogenic process throughout life relies on the proper regulation of the stem cell maintenance and differentiation. A stem cell function during steady state of mouse spermatogenesis might reside in undifferentiated spermatogonia.
Here we show that Nanos2 plays an essential role in the maintenance of these cells. Conditional disruption of postnatal Nanos2 results in the depletion of spermatogonial cell reserves, whereas mouse testes in which Nanos2 has been overexpressed show an accumulation of spermatogonia with undifferentiated properties. Moreover, lineage tracing experiments revealed that endogenous Nanos2-expressing cells give rise to all spermatogenic cell types over long periods, indicating that a Nanos2-expressing subpopulation of undifferentiated spermatogonia functions as the stem cells in vivo. Taken together, we conclude from our current data that Nanos2 is expressed in these actual stem cells and function to maintain this undifferentiated stem cell population in part by suppressing their differentiation.

　The results of this research were published on line in Science on September 11th.

	The RNA-Binding Protein NANOS2 is Required to Maintain Murine Spermatogonial Stem Cells
	Aiko Sada, Atsushi Suzuki, Hitomi Suzuki, Yumiko Saga.
	DOI: 10.1126/science.1172645

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Mammalian Development Laboratory,Saga Laboratory