Understanding the regulatory networks for germ cell fate specification is necessary to developing strategies for improving the efficiency of germ cell production in vitro. In this study, we developed a coupled screening strategy that took advantage of an arrayed bi-molecular fluorescence complementation (BiFC) platform for protein-protein interaction screens and epiblast-like cell (EpiLC)-induction assays using reporter mouse embryonic stem cells (mESCs). Investigation of candidate interaction partners of core human pluripotent factors OCT4, NANOG, KLF4 and SOX2 in EpiLC differentiation assays identified novel primordial germ cell (PGC)-inducing factors including BEN-domain (BEND/Bend) family members. Through RNA-seq, ChIP-seq, and ATAC-seq analyses, we showed that Bend5 worked together with Bend4 and helped mark chromatin boundaries to promote EpiLC induction in vitro. Our findings suggest that BEND/Bend proteins represent a new family of transcriptional modulators and chromatin boundary factors that participate in gene expression regulation during early germline development.
Animals ; Cell Differentiation/genetics* ; Chromatin/metabolism* ; Embryonic Stem Cells ; Germ Cells/metabolism* ; Germ Layers/metabolism* ; Mice

It is not fully clear why there is a higher contribution of pluripotent stem cells (PSCs) to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we show that not only embryonic stem cells (ESCs) but also induced pluripotent stem cells (iPSCs) can generate F0 nearly 100% donor cell-derived mice by 4-cell stage embryo injection, and the approach has a "dose effect". Through an analysis of the PSC-secreted proteins, Activin A was found to impede epiblast (EPI) lineage development while promoting trophectoderm (TE) differentiation, resulting in replacement of the EPI lineage of host embryos with PSCs. Interestingly, the injection of ESCs into blastocysts cultured with Activin A (cultured from 4-cell stage to early blastocyst at E3.5) could increase the contribution of ESCs to the chimera. The results indicated that PSCs secrete protein Activin A to improve their EPI competency after injection into recipient embryos through influencing the development of mouse early embryos. This result is useful for optimizing the chimera production system and for a deep understanding of PSCs effects on early embryo development.
Activins ; metabolism ; Animals ; Cells, Cultured ; Embryonic Development ; Germ Layers ; metabolism ; Mice ; Pluripotent Stem Cells ; cytology ; metabolism

CRISPR-Cas Systems ; Embryo, Mammalian ; cytology ; metabolism ; Germ Cells ; cytology ; metabolism ; Humans ; RNA Editing ; genetics

Animals ; Cell Culture Techniques ; Cell Differentiation ; Cell Proliferation ; Embryonic Stem Cells ; cytology ; metabolism ; Germ Cells ; cytology ; metabolism ; Germ Layers ; cytology ; metabolism ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; Mice ; Pluripotent Stem Cells ; cytology ; metabolism ; Reproductive Techniques, Assisted

OBJECTIVETo explore the characteristics and distribution of GATA-4 in the testis of male mice.

METHODSParaffin sections were obtained from the testes of 24 male B6SJLF1/J mice, aged 0 day (n = 6), 2 weeks (n = 6), 4 weeks (n = 6) and 6 weeks (n = 6), and the expressions of GATA-4 in the testis were observed by the immunohistochemical ABC method and DAB visualization at different times.

RESULTSPositive expressions of GATA4 were found in the Sertoli cells and Leydig cells of all the mice, but significantly higher in the 4- and 6-week-old than in the 0-day and 2-week-old groups (P < 0.01). And they were also observed in the germ cells of the 4- and 6-week-old mice, significantly higher in the latter than in the former (P < 0.01).

CONCLUSIONGATA-4 exists in the testis of male mice, which has provided a morphological base for sex determination and differentiation and hormone regulation in the testis.

Animals ; Cell Differentiation ; GATA4 Transcription Factor ; metabolism ; Germ Cells ; metabolism ; Leydig Cells ; metabolism ; Male ; Mice ; Sertoli Cells ; metabolism ; Testis ; cytology ; metabolism

Although somatic cells can be reprogrammed to pluripotent stem cells (PSCs) with pure chemicals, authentic pluripotency of chemically induced pluripotent stem cells (CiPSCs) has never been achieved through tetraploid complementation assay. Spontaneous reprogramming of spermatogonial stem cells (SSCs) was another non-transgenic way to obtain PSCs, but this process lacks mechanistic explanation. Here, we reconstructed the trajectory of mouse SSC reprogramming and developed a five-chemical combination, boosting the reprogramming efficiency by nearly 80- to 100-folds. More importantly, chemical induced germline-derived PSCs (5C-gPSCs), but not gPSCs and chemical induced pluripotent stem cells, had authentic pluripotency, as determined by tetraploid complementation. Mechanistically, SSCs traversed through an inverted pathway of in vivo germ cell development, exhibiting the expression signatures and DNA methylation dynamics from spermatogonia to primordial germ cells and further to epiblasts. Besides, SSC-specific imprinting control regions switched from biallelic methylated states to monoallelic methylated states by imprinting demethylation and then re-methylation on one of the two alleles in 5C-gPSCs, which was apparently distinct with the imprinting reprogramming in vivo as DNA methylation simultaneously occurred on both alleles. Our work sheds light on the unique regulatory network underpinning SSC reprogramming, providing insights to understand generic mechanisms for cell-fate decision and epigenetic-related disorders in regenerative medicine.
Male ; Mice ; Animals ; Cellular Reprogramming/genetics* ; Tetraploidy ; Pluripotent Stem Cells/metabolism* ; Induced Pluripotent Stem Cells/metabolism* ; DNA Methylation ; Spermatogonia/metabolism* ; Germ Cells/metabolism*

Lectins are glycoproteins that specifically bind carbohydrate structures and may participate in the biodefense mechanisms of fish. In this study, the binding of three lectins, Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), Bandeiraea simplicifolia BS-1 (isolectin B4), Triticum vulgaris (WGA), Arachis hypogaea (PNA) and Ulex europaeus (UEA-I) were studied in the gill, liver, intestine, kidney, heart, and spleen of the flat fish Paralichthys olivaceus. DBA was detected in intestinal mucous cells, as well as in gill epithelial and mucous cells. It was weakly detected in renal tubule epithelial cells and in bile duct epithelial cells. The strong SBA staining was seen in the intestinal club cells, in bile duct epithelial cells and renal tubule epithelial cells. There were intense positive reactions for isolectin B4 in gill epithelial and mucous cells, and the strong isolectin B4 staining was seen in epithelial cells of the bile duct and intestine. The strong WGA staining was seen in the gill mucosal cells, sinusoid, renal tubule epithelial cells and mucosal cells of the intestine. UEA-I was detected in the gill epithelial and mucosal cells, bile duct epithelial cells and renal tubular epithelial cells. These results suggest that the six lectins examined were localized in the covering epithelia of the various organs of the flat fish and they may participate in the biodefense mechanism of the intra body surface in which is exposed to various antigens.
Animals ; Epithelial Cells/metabolism ; Flatfishes/*metabolism ; Histocytochemistry/veterinary ; Lectins/*metabolism ; Mucus/metabolism ; Peanut Agglutinin/metabolism ; Plant Lectins/metabolism ; Soybean Proteins/metabolism ; Wheat Germ Agglutinins/metabolism

Stimulated by retinoic acid gene 8 (STRA8) is specifically expressed in mammalian germ cells before their transition from mitosis to meiosis. STRA8 expression is observed only in the postnatal testis. Single nucleotide polymorphisms but no mutations were identified in the coding or proximal promoter region of STRA8 in some gonadal dysgenesis patients. Studies on the teratocarcinoma cells and embryonic stem cells (ESC) transfected with STRA8-EGFP, a fusion construct harboring the promoter and coding region of the enhanced green fluorescence protein, have shown that the STRA8-EGFP positive cells may undergo meiosis, develop into sperm and generate live offspring mice. STRA8-EGFP positive cells derived from the bone marrow are able to differentiate into spermatogenic cells, but arrest in the premeiotic stage, and those from the adult mouse testis, when cultured in ESC culture conditions, may acquire ESC properties, pluripotency and redifferentiation capacity and act as a new stem cell source for tissue regeneration. The presence of oocytes renewed in postnatal mouse ovaries calls in question the absence of STRA8 in postnatal mouse ovaries.
Adaptor Proteins, Signal Transducing ; Animals ; Biomarkers ; metabolism ; Cells, Cultured ; Female ; Germ Cells ; cytology ; metabolism ; Humans ; Male ; Mice ; Oocytes ; metabolism ; Proteins ; metabolism ; Testis ; cytology ; metabolism

Nuclease-based gene editing technologies have opened up opportunities for correcting human genetic diseases. For the first time, scientists achieved targeted gene editing of mitochondrial DNA in mouse oocytes fused with patient cells. This fascinating progression may encourage the development of novel therapy for human maternally inherent mitochondrial diseases.
Animals ; DNA, Mitochondrial ; genetics ; Embryo, Mammalian ; metabolism ; Genome ; Germ Cells ; metabolism ; Humans ; Mitochondrial Diseases ; genetics ; therapy ; RNA Editing ; genetics

OBJECTIVETo investigate whether adipose-derived stem cells (ADSCs) induced by retinoic acid (RA) in vitro express primordial germ cell marker alkaline phosphatase (ALP) and vasa.

METHODSADSCs were isolated from adult female SD rats and cultured in vitro. The third passage of ADSCs was identified by adipogenic differentiation, osteogenic differentiation and cell surface marker detection. The ADSCs were treated with 1×10(-5), 1×10(-6), or 1×10(-7) mol/L RA for 7 or 14 days, and the cellular expression of ALP was detected. vasa mRNA expression in ADSCs treated with 1×10(-5) mol/L RA for 7 days was detected using RT-PCR.

RESULTSThe OD value of ADSCs treated with 1×10(-5), 1×10(-6), or 1×10(-7) mol/L RA was 0.59∓0.04, 0.27∓0.07, and 0.15∓0.03 after a 7-day treatment, and was 0.42∓0.02, 0.34∓0.01, and 0.19∓0.02 after a 14-day treatment, respectively, demonstrating significantly enhanced ALP expression in RA-treated ADSCs compared with that in the control cells (0.07∓0.01 and 0.07∓0.01 at 7 and 14 days, respectively, P<0.01). The ADSCs showed a negative vasa mRNA expression after 1×10(-5) mol/L RA treatment for 7 days.

CONCLUSIONRA-induced ADSCs express ALP, a marker of primordial germ cells, but does not express the primordial germ cell marker vasa.

Adipose Tissue ; cytology ; Adult Stem Cells ; cytology ; enzymology ; Alkaline Phosphatase ; metabolism ; Animals ; Cell Differentiation ; Cells, Cultured ; Female ; Germ Cells ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tretinoin ; pharmacology