Functional expression and germline atransmission of a human chromosome fragment in chimaeric mice

Abstract

Human chromosomes or chromosome fragments derived from normal fibroblasts were introduced into mouse embryonic stem (ES) cells via microcell-mediated chromosome transfer (MMCT) and viable chimaeric mice were produced from them. Transferred chromosomes were stably retained, and human genes, including immunoglobulin (Ig) kappa, heavy, lambda genes, were expressed in proper tissue-specific manner in adult chimaeric tissues. In the case of a human chromosome (hChr.) 2-derived fragment, it was found to be transmitted to the offspring through the germline. Our study demonstrates that MMCT allows for introduction of very large amounts of foreign genetic material into mice. This novel procedure will facilitate the functional analyses of human genomes in vivo.

Position of human chromosomes is conserved in mouse nuclei indicating a species-independent mechanism for maintaining genome organization

“…An in vitro assay system using MMCT was used to identify the imprinting status of various genes on human chromosomes and A9 monochromosomal hybrids appropriately maintained the parental expression pattern and methylation status of the human imprinted genes (Kugoh, et al 1999;Inoue, et al 2001). Mouse ES cells containing fragments of human chromosomes 2, 14 and 22 showed tissue specific expression of the human genes in chimeric mice, suggesting a whole chromosome might also exhibit expression in the mouse (Tomizuka, et al 1997). MMCT that was used to generate a mouse model of Down syndrome recapitulated the phenotype, providing further evidence for transcriptional activity of human chromosomes in nuclei from different species (O'Doherty, et al 2005).…”

Chromosome engineering: prospects for gene therapy

“…14,15,17 The production of mice harboring a human chromosome(s) showing correct tissue-specific human immunoglobulin gene expression provides the first mouse model addressing the capacity of a human marker chromosome to deliver tissue specific transgene expression. The Ishida and Marynen laboratories have now taken this technology one step further by modifying human marker chromosomes using the Cre/loxP system to introduce genes that were stably expressed following transfer of the modified marker chromosome into mice.…”

“…The existence of spontaneously arising or radiation-induced human marker chromosomes offers an alternative starting point for deriving a chromosomebased vector system. [11][12][13][14][15][16][17] A further chromosome engineering technology under development relies upon integration of exogenous DNA into the centromere region of a host mouse or human chromosome. Amplification of DNA at the integration site can result in chromosome breakage events, producing new large chromosomes typically in the 60-400 Mb size range.…”

The use of chromosome-based vectors for animal transgenesis

“…1 Transferred hCFs were stably maintained as an extra chromosome in the somatic cells of mice and the human genes included in them were expressed under proper tissue-specific regulation. In some cases they could be transmitted through the mouse germline, resulting in the establishment of novel mouse strains (trans-chromosomic (Tc) mice) containing a heritable hCF.…”