Reprogramming of chimpanzee fibroblasts into a multipotent cancerous but not fully pluripotent state by transducing iPSC factors in 2i/LIF culture.

To induce and maintain naïve pluripotency in mouse embryonic and induced pluripotent stem cells (ESCs/iPSCs), chemically defined N2B27 medium with PD0325901, CHIR99021, and leukemia inhibitory factor (2i/LIF) is a classic and simple condition. However, this method cannot be simply extrapolated to human ESCs/iPSCs that are principally stabilized in primed pluripotency and become primitive neuroepithelium-like cells in N2B27+2i/LIF culture. Here, we assessed iPSC reprogramming of fibroblasts from chimpanzee, our closest living relative, in N2B27+2i/LIF culture.

Sphere-formation culture of testicular germ cells in the common marmoset, a small New World monkey.

Spermatogonia are specialized cells responsible for continuous spermatogenesis and the production of offspring. Because of this biological property, in vitro culture of spermatogonia provides a powerful methodology to advance reproductive biology and engineering. However, methods for culturing primate spermatogonia are poorly established.

Gene expression ontogeny of spermatogenesis in the marmoset uncovers primate characteristics during testicular development.

Mammalian spermatogenesis has been investigated extensively in rodents and a strictly controlled developmental process has been defined at cellular and molecular levels. In comparison, primate spermatogenesis has been far less well characterized. However, important differences between primate and rodent spermatogenesis are emerging so it is not always accurate to extrapolate findings in rodents to primate systems.

Small RNA profiling and characterization of piRNA clusters in the adult testes of the common marmoset, a model primate.

Small RNAs mediate gene silencing by binding Argonaute/Piwi proteins to regulate target RNAs. Here, we describe small RNA profiling of the adult testes of Callithrix jacchus, the common marmoset. The most abundant class of small RNAs in the adult testis was piRNAs, although 353 novel miRNAs but few endo-siRNAs were also identified.

Generation of germ cells in vitro in the era of induced pluripotent stem cells.

Induced pluripotent stem cells (iPSCs) are stem cells that can be artificially generated via "cellular reprogramming" using gene transduction in somatic cells. iPSCs have enormous potential in stem-cell biology as they can give rise to numerous cell lineages, including the three germ layers. An evaluation of germ-line competency by blastocyst injection or tetraploid complementation, however, is critical for determining the developmental potential of mouse iPSCs towards germ cells.

Aberrant gene expression and sexually incompatible genomic imprinting in oocytes derived from XY mouse embryonic stem cells in vitro.

Mouse embryonic stem cells (ESCs) have the potential to differentiate into germ cells (GCs) in vivo and in vitro. Interestingly, XY ESCs can give rise to both male and female GCs in culture, irrespective of the genetic sex. Recent studies showed that ESC-derived primordial GCs contributed to functional gametogenesis in vivo; however, in vitro differentiation techniques have never succeeded in generating mature oocytes from ESCs due to cryptogenic growth arrest during the preantral follicle stages of development.

Derivation of induced pluripotent stem cells by retroviral gene transduction in mammalian species.

Pluripotent stem cells can provide us with an enormous cell source for in vitro model systems for development. In 2006, new methodology was designed to generate pluripotent stem cells directly from somatic cells, and these cells were named induced pluripotent stem cells (iPSCs). This method consists of technically simple procedures: donor cell preparation, gene transduction, and isolation of embryonic stem cell-like colonies.

Cell-intrinsic reprogramming capability: gain or loss of pluripotency in germ cells.

In multicellular organisms, germ cells are an extremely specialized cell type with the vital function of transmitting genetic information across generations. In this respect, they are responsible for the perpetuity of species, and are separated from somatic lineages at each generation. Interestingly, in the past two decades research has shown that germ cells have the potential to proceed along two distinct pathways: gametogenesis or pluripotency.

Molecular signatures to define spermatogenic cells in common marmoset (Callithrix jacchus).

Germ cell development is a fundamental process required to produce offspring. The developmental program of spermatogenesis has been assumed to be similar among mammals. However, recent studies have revealed differences in the molecular properties of primate germ cells compared with the well-characterized mouse germ cells.