Abstract: The present invention provides clonal pluripotent hepatic stem cells using flow cytometry and in vitro single-cell-based assays. These cells possess multilineage differentiation potential and self-renewing capability. These cells could be clonally propagated in culture, where they continuously produced hepatocytes and cholangiocytes as descendants while maintaining primitive stem cells. When cells that expanded in vitro were transplanted into recipient animals, they morphologically and functionally differentiated into hepatocytes and cholangiocytes, with reconstitution of hepatocyte and bile duct structures. Furthermore, these cells differentiated into pancreatic ductal and acinar cells or intestinal epithelial cells when transplanted into pancreas or duodenal wall. These data indicate that self-renewing multipotent stem cells persist in the developing mouse liver and that such cells can be induced to become cells of other organs of endodermal origin under appropriate microenvironment.

Abstract: The present invention includes methods of performing ex vivo expansion of gene-modified hematopoietic stem cells which are useful for many applications involving bone marrow transplantation and ex vivo gene therapy. The present invention further includes the gene-modified hematopoietic stem cells that are used and produced by such methods. Such gene-modified hematopoietic stem cells can also contain a second heterologous gene. In addition, the present invention also includes methods of engrafting the gene-modified hematopoietic stem cells of the present invention into animals, including for ex vivo gene therapy and for reconstitution of hematopoietic cells in ablated mammals. The present invention also provides a method of isolating stem cells.

Abstract: A method and substance for regulating expansion of a stem cell, such as a hematopoietic stem cell, is provided. Therefore, a method is provided for regulating expansion of a stem cell, such as a hematopoietic stem cell, a germ line stem cell, or a neural stem cell, comprising the steps of (A) providing, to the stem cell, Bmi-1 or a variant or fragment thereof and/or a Bmi-1 regulating agent in an amount sufficient for regulation of the expansion of the stem cell and (B) culturing the stem cell for a time sufficient for the regulation of expansion.

Abstract: The present invention provides clonal pluripotent hepatic stem cells using flow cytometry and in vitro single-cell-based assays. These cells possess multilineage differentiation potential and self-renewing capability; These cells could be clonally propagated in culture, where they continuously produced hepatocytes and cholanglocytes as descendants while maintaining primitive stem cells. When cells that expanded In vitro were transplanted into recipient animals, they morphologically and functionally differentiated into hepatocytes and cholanglocytes, with reconstitution of hepatocyte and bile duct structures. Furthermore, these cells differentiated into pancreatic ductal and acinar cells or intestinal epithelial cells when transplanted into pancreas or duodenal wall. These data indicate that self-renewing multipotent stem cells persist in the developing mouse liver and that such cells can be Induced to become cells of other organs of endodermal origin under appropriate microenvironment.

Abstract: The present invention provides a method for developing a human T cell-engrafted mouse, which includes transplanting a human-derived bone tissue into an inbred line mouse deficient in immune cells, and a human T cell-engrafted mouse obtainable by the method. The present invention also provides a method for preparing an HIV-infected mouse model, which includes infecting the human T cell-engrafted mouse with HIV, and an HIV-infected mouse model obtainable by the method.

Abstract: The present invention provides a method of cloning a protein coding for a membrane protein without the need of using anyantibody or ligand. The method of cloning a membrane protein comprises selecting a protein having a signal sequence, using a DNA coding for the signal sequence and N-terminal sequence of the protein as the reporter gene, and screening for a gene for a protein having a transmembrane domain(s). The present invention is concerned also with the CDNA obtained by using such method, a vector containing the DNA, a transformant as transformed with the vector, and the transcription product of the DNA as produced by the transformant.

Abstract: The present invention provides a method for developing a human T cell-engrafted mouse, which includes transplanting a human-derived bone tissue into an inbred line mouse deficient in immune cells, and a human T cell-engrafted mouse obtainable by the method. The present invention also provides a method for preparing an HIV-infected mouse model, which includes infecting the human T cell-engrafted mouse with HIV, and an HIV-infected mouse model obtainable by the method.