Submitted on January 22, 2007
Accepted on June 26, 2007
Transfer of a Human Chromosomal Vector from a Hamster Cell Line to a Mouse Embryonic Stem Cell Line
Marianna Paulis 1,
Mirella Bensi 2,
Chiara Mondello 3,
Donata Orioli 3,
Giuliano Mazzini 3,
Maurizio D'Incalci 4,
Cristiano Falcioni 4,
Enrico Radaelli 5,
Eugenio Erba 3,
Elena Raimondi 2,
Luigi De Carli 2*
1 Dipartimento di Genetica e Microbiologia "Adriano Buzzati Traverso" Università degli Studi di Pavia, Italy.; Istituto di Tecnologie Biomediche del CNR di Segrate, Milano, Italy.
2 Dipartimento di Genetica e Microbiologia "Adriano Buzzati Traverso" Università degli Studi di Pavia, Italy.
3 Istituto di Genetica Molecolare del CNR di Pavia, Italy.
4 Department of Oncology Istituto di Ricerche Farmacologiche "Mario Negri " di Milano, Italy.
5 Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria Università degli Studi di Milano, Italy.
* To whom correspondence should be addressed. E-mail: decarli{at}ipvgen.unipv.it.
 |
Abstract |
|---|
Two trans-chromosomic mouse embryonic stem (ES) sublines (ESMClox1.5 and ESMClox2.1) containing a human minichromosome (MC) were established from a sample of hybrid colonies isolated in fusion experiments between a normal diploid mouse ES line and a Chinese hamster ovary (CHO) line carrying the MC. DNA cytometric and chromosome analyses of ESMClox1.5 and ESMClox2.1 indicated a mouse chromosome complement with a heteroploid constitution in a subtetraploid range; the karyotypes showed various degrees of polysomies for different chromosomes. A single copy of the MC was found in the majority of cells in all the isolated hybrid colonies and was stably maintained in the established sublines for more than 100 cell generations either with or without the selective agent.
No significant differences from the ES parental cells were observed in growth characteristics of the trans-chromosomic ES sublines. ESMClox1.5 cells were unable to grow in soft agar; when cultured in hanging drops they formed embryoid bodies, and inoculated in nude mice they produced teratomas. They are able to express the early development markers Oct4 and Nanog, as demonstrated by RT-PCR assay. All these are features in common with the ES parental line. Further research using the trans-chromosomic ES sublines here described may allow gene expression studies on transferred human minichromosomes and could shed light on the relationships between ploidy, pluripotency, cell transformation and tumorigenesis.
Key Words.
Human chromosomal vector, Mouse embryonic stem cell, Cell fusion, Tran-chromosomic mouse ES cell line, Ploidy variation, Pluripotent gene markers
