Maintenance of feeder free anchorage independent cultures of ES and iPS cells by retinol/vitamin A.

Pluripotent embryonic stem (ES) cells derived from mammalian blastocyst and the adult fibroblast derived induced pluripotent stem (iPS cells) exhibit complete potential to form cells representing all the primary germ layers such as mesoderm, endoderm and ectoderm. These cells are usually co-cultured with mouse embryonic fibroblast feeders to prevent spontaneous differentiation. Feeder free cultures can provide substantial advantage to improve the efficiency and consistency of the culture conditions.

Multiple ovarian transplants to rescue a transgenic line of mice.

Transgenic mice are useful tools for studying gene function and regulation but can be difficult to successfully breed. To 'rescue' transgenic lines that are difficult to propagate, researchers use a variety of techniques. One method is ovarian transplant, in which researchers remove ovaries from a donor transgenic mouse, cryopreserve the ovarian tissue, transplant this tissue into histocompatible female mice and breed these recipient females.

Suppression of ES cell differentiation by retinol (vitamin A) via the overexpression of Nanog.

Embryonic stem cells (ESCs) derived from the inner cell mass of blastocysts maintain their pluripotency through a complex interplay of different signaling pathways and transcription factors including Leukemia Inhibitory Factor (LIF), homeo-domain protein Nanog and POU-domain-containing transcription factor Oct3/4. LIF can maintain the self-renewal of mouse ESCs by activating the Jak/Stat3 pathway; however, it is dispensable for human ESCs. Nanog, a homeo-domain transcription factor alone is sufficient for sustaining the self-renewal of ESCs.