Abstract: Isolated mammalian stem cells sustainable in culture under glycolytic conditions and which maintain the potential to differentiate are provided. Further encompassed by the invention are functionally distinct subpopulations of stem cells with increased differentiation permissiveness.

Abstract: This invention provides a method of using a porcine stem cell factor (PSCF), which may also be termed porcine “steel” factor, which is preferably membrane-bound PSCF on transfected murine STO feeder cells, for establishing pluripotent or totipotent porcine cell lines, especially for the culture of porcine primordial germ cells (PGCs).

Abstract: This invention relates to newly identified polynucleotides, polypeptides encoded by such polynucleotides, the use of such polynucleotides and polypeptides, as well as the production and isolation of such polynucleotides and polypeptides. More particularly, the polynucleotides and polypeptides of the present invention have been identified as porcine stem cell factors, and in particular membrane-bound porcine stem cell factors, and still more particularly as being involved in the culture of pluripotent or totipotent porcine cells.

Abstract: A gene trap construct for identification of genes whose activity is regulated upon a cellular transition event which comprises in downstream sequence (i) a cassette having a functional splice acceptor, a translation stop sequence and an internal ribosome entry site and (ii) a promoterless protein coding sequence encoding at least one polypeptide providing positive and negative selection traits. A method for identification of genes whose activity is regulated upon a cellular transition event by introducing the gene trap construct into a cell and observing expression of the positive and/or negative selection traits before and after the transition event.