A model system to study genomic imprinting of human genes

^*Department of Genetics, Case Western Reserve University School of Medicine, and ^†Center for Human Genetics, University Hospitals of Cleveland, 10900 Euclid Avenue, Cleveland, OH 44106-4955; and ^‡Department of Human Genetics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263

Edited by Francis H. Ruddle, Yale University, New Haven, CT, and approved October 2, 1998 (received for review December 19, 1997)

Abstract

Somatic-cell hybrids have been shown to maintain the correct epigenetic chromatin states to study developmental globin gene expression as well as gene expression on the active and inactive X chromosomes. This suggests the potential use of somatic-cell hybrids containing either a maternal or a paternal human chromosome as a model system to study known imprinted genes and to identify as-yet-unknown imprinted genes. Testing gene expression by using reverse transcription followed by PCR, we show that functional imprints are maintained at four previously characterized 15q11–q13 loci in hybrids containing a single human chromosome 15 and at two chromosome 11p15 loci in hybrids containing a single chromosome 11. In contrast, three γ-aminobutyric acid type A receptor subunit genes in 15q12–q13 are nonimprinted. Furthermore, we have found that differential DNA methylation imprints at the SNRPN promoter and at a CpG island in 11p15 are also maintained in somatic-cell hybrids. Somatic-cell hybrids therefore are a valid and powerful system for studying known imprinted genes as well as for rapidly identifying new imprinted genes.

Beckwith–Weidemann syndrome/gene expression/imprinting/methylation/Prader–Willi syndrome

Footnotes

↵ § Present address: Department of Pediatrics, Hokkaido University School of Medicine, Kita 15 Nishi 7, Kita-ku, Sapporo 060, Japan.
↵ ¶ To whom reprint requests should be addressed at: Department of Genetics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106. e-mail: rxn19{at}po.cwru.edu.
This paper was submitted directly (Track II) to the Proceedings Office.
ABBREVIATIONS:

AS,

Angelman syndrome;

PWS,

Prader–Willi syndrome;

RT-PCR,

reverse transcription–PCR;

UPD,

uniparental disomy