1. ¹Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Tottori, Japan
2. ²Department of Human Genome Science, Graduate School of Medical Science, Tottori University, Yonago, Tottori, Japan
3. ³Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
4. ⁴The Institute of Physical and Chemical Research (RIKEN), Bioresource Center, Ibaraki, Japan
5. ⁵Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago, Tottori, Japan
6. ⁶Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Tottori, Japan
7. ⁷Laboratory of Biosystems and Cancer, National Cancer Institute, Bethesda, MD, USA

Correspondence: Professor M Oshimura, Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishicho, Nishimachi 86 Yonago shi, Yonago, Tottori 683-8503, Japan. E-mail: oshimura@grape.med.tottori-u.ac.jp

⁸Current address: Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA.

Received 21 May 2007; Revised 10 October 2007; Accepted 19 November 2007; Published online 28 February 2008.

Abstract

Human artificial chromosomes (HACs) have several advantages as gene therapy vectors, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts including regulatory elements. Multipotent germline stem (mGS) cells have a great potential for gene therapy because they can be generated from an individual's testes, and when reintroduced can contribute to the specialized function of any tissue. As a proof of concept, we herein report the functional restoration of a genetic deficiency in mouse p53-/- mGS cells, using a HAC with a genomic human p53 gene introduced via microcell-mediated chromosome transfer. The p53 phenotypes of gene regulation and radiation sensitivity were complemented by introducing the p53-HAC and the cells differentiated into several different tissue types in vivo and in vitro. Therefore, the combination of using mGS cells with HACs provides a new tool for gene and cell therapies. The next step is to demonstrate functional restoration using animal models for future gene therapy.