Reprogramming p53-Deficient Germline Stem Cells Into Pluripotent State by Nanog.

Cultured mouse spermatogonial stem cells (SSCs), also known as germline stem cells (GSCs), revert back to pluripotent state either spontaneously or upon being modified genetically. However, the reprogramming efficiencies are low, and the underlying mechanism remains poorly understood. In the present study, we conducted transcriptomic analysis and found that many transcription factors and epigenetic modifiers were differentially expressed between GSCs and embryonic stem cells.

Gene knockout of Zmym3 in mice arrests spermatogenesis at meiotic metaphase with defects in spindle assembly checkpoint.

ZMYM3, a member of the MYM-type zinc finger protein family and a component of a LSD1-containing transcription repressor complex, is predominantly expressed in the mouse brain and testis. Here, we show that ZMYM3 in the mouse testis is expressed in somatic cells and germ cells until pachytene spermatocytes. Knockout (KO) of Zmym3 in mice using the CRISPR-Cas9 system resulted in adult male infertility.

MicroRNA-202 maintains spermatogonial stem cells by inhibiting cell cycle regulators and RNA binding proteins.

miRNAs play important roles during mammalian spermatogenesis. However, the function of most miRNAs in spermatogenesis and the underlying mechanisms remain unknown. Here, we report that miR-202 is highly expressed in mouse spermatogonial stem cells (SSCs), and is oppositely regulated by Glial cell-Derived Neurotrophic Factor (GDNF) and retinoic acid (RA), two key factors for SSC self-renewal and differentiation.

BMP4 Cooperates with Retinoic Acid to Induce the Expression of Differentiation Markers in Cultured Mouse Spermatogonia.

Spermatogenesis is sustained by the proliferation and differentiation of spermatogonial stem cells (SSCs). However, the molecules controlling these processes remain largely unknown. Here, we developed a simplified high concentration serum-containing system for the culture of mouse SSCs.

Retinoic Acid Is Sufficient for the In Vitro Induction of Mouse Spermatocytes.

Meiosis is the key step in gametogenesis. However, the mechanism of mammalian meiosis remains poorly understood due to the lack of an in vitro model. Here, we report that retinoic acid (RA) is sufficient for inducing leptotene/zygotene spermatocytes from cultured mouse spermatogonial stem cells.

Transcription Factor RFX2 Is a Key Regulator of Mouse Spermiogenesis.

The regulatory factor X (RFX) family of transcription factors is crucial for ciliogenesis throughout evolution. In mice, Rfx1-4 are highly expressed in the testis where flagellated sperm are produced, but the functions of these factors in spermatogenesis remain unknown. Here, we report the production and characterization of the Rfx2 knockout mice.

Generation of male germ cells from mouse induced pluripotent stem cells in vitro.

Germ cells are the only cell type that passes genetic information to the next generation. In most metazoan species, primordial germ cells (PGCs) were induced from epiblasts by signals from the neighboring tissues. In vitro derivation of germ cells from the pluripotent stem cells (PSCs) such as embryonic stem cells (ESCs) and induced PSCs (iPSCs) are of great values for the treatment of infertility, for animal breeding, and for studying the mechanism of germ cell development.

SYCP3-like X-linked 2 is expressed in meiotic germ cells and interacts with synaptonemal complex central element protein 2 and histone acetyltransferase TIP60.

Meiosis is the process by which diploid germ cells produce haploid gametes. A key event is the formation of the synaptonemal complex. In the pachytene stage, the unpaired regions of X and Y chromosomes form a specialized structure, the XY body, within which gene expression is mostly silenced.

Dynamics of 5-hydroxymethylcytosine during mouse spermatogenesis.

Little is known about how patterns of DNA methylation change during mammalian spermatogenesis. 5 hmC has been recognized as a stable intermediate of DNA demethylation with potential regulatory functions in the mammalian genome. However, its global pattern in germ cells has yet to be addressed.

HSF2BP represses BNC1 transcriptional activity by sequestering BNC1 to the cytoplasm.

Basonuclin (BNC1), a zinc finger transcriptional factor, is essential for mouse spermatogenesis. However, the regulatory mechanisms of BNC1 in spermatogenesis are poorly understood. In this study, we identified HSF2BP, a testis-specific binding protein of HSF2, as a binding partner of BNC1 by using yeast two-hybrid screening.

Mining and characterization of ubiquitin E3 ligases expressed in the mouse testis.

Background: Ubiquitin-mediated protein modification and degradation are believed to play important roles in mammalian spermatogenesis. The catalogues of ubiquitin activating enzymes, conjugating enzymes, and ligases (E3s) have been known for mammals such as mice and humans. However, a systematic characterization of E3s expressed during spermatogenesis has not been carried out.

Mouse Fem1b interacts with and induces ubiquitin-mediated degradation of Ankrd37.

Ankyrin repeat domain 37 (Ankrd37), a protein containing ankyrin repeats (ARs) and a putative nuclear localization signal (NLS), is highly conserved from zebrafish to humans. In mouse testes, Ankrd37 protein was initially present in the cytoplasm of elongating spermatids, and finally restricted to the nuclei of spermatozoa during spermatogenesis. Ankrd37 bound to feminization 1 homolog b (Fem1b) as indicated by yeast two-hybrid screening and co-immunoprecipitation assays.

SLXL1, a novel acrosomal protein, interacts with DKKL1 and is involved in fertilization in mice.

Background: Spermatogenesis is a complex cellular developmental process which involves diverse families of genes. The Xlr (X-linked, lymphocyte regulated) family includes multiple members, only a few of which have reported functions in meiosis, post-meiotic maturation, and fertilization of germ cells. Slx-like1 (Slxl1) is a member of the Xlr family, whose expression and function in spermatogenesis need to be elucidated.

piRNA profiling during specific stages of mouse spermatogenesis.

PIWI-interacting RNAs (piRNAs) are a class of small RNAs abundantly expressed in animal gonads. piRNAs that map to retrotransposons are generated by a "ping-pong" amplification loop to suppress the activity of retrotransposons. However, the biogenesis and function of other categories of piRNAs have yet to be investigated.

Male germ cell-specific protein Trs4 binds to multiple proteins.

Temperature-related sequence 4 (Trs4) has been identified as a testis-specific gene with expression sensitive to the abdominal temperature changes induced by artificial cryptorchidism. In murine testes, Trs4 mRNA was detected in round spermatids and its protein was localized mainly in the elongating spermatids as well as in the acrosomes and tails of mature spermatozoa. Using a yeast two-hybrid screening system, we identified Rshl-2, Gstmu1, and Ddc8 as putative binding partners of the Trs4 protein in mouse testes.

Uncoupling protein 2 protects testicular germ cells from hyperthermia-induced apoptosis.

The mRNA of the mitochondrial uncoupling protein 2 (UCP2) was up-regulated by cryptorchidism, a testicular hyperthermic condition under which germ cells undergo severe apoptosis. We investigated whether UCP2 was able to protect germ cells from hyperthermia-induced apoptosis. UCP2 was predominantly present in elongate spermatids under normal conditions, and was detected in all germ cells with its level significantly increased if the testes were exposed to 43 degrees C for 5 min.

RNF151, a testis-specific RING finger protein, interacts with dysbindin.

RING finger proteins play important roles in spermatogenesis. Here, we report that a novel RING finger protein RNF151, with a C3HC4-type RING finger domain, a putative nuclear localization signal (NLS), and a TRAF-type zinc finger domain, was exclusively expressed in the mouse testis and developmentally regulated during spermatogenesis. While RNF151 mRNA was present in round spermatids, its protein was expressed in elongating spermatids of the stage VIII-IX seminiferous tubules.

In vitro propagation of spermatogonial stem cells from KM mice.

Spermatogonial stem cells (SSCs) are a unique type of stem cells in that they transmit genetic information to the next generation by producing sperms. Studies of SSC proliferation and differentiation have been hampered by the inability of reconstructing these processes in vitro, particularly in a serum-free culture system. Several groups have reported the long term culture of SSCs during which SSCs self-renew and restore spermatogenesis when transplanted back to recipient testes.