title: Gene-specific vulnerability to imprinting variability in human embryonic stem cell lines.
abstract: Disregulation of imprinted genes can be associated with tumorigenesis and altered cell differentiation capacity and so could provide adverse outcomes for stem cell applications. Although the maintenance of mouse and primate embryonic stem cells in a pluripotent state has been reported to disrupt the monoallelic expression of several imprinted genes, available data have suggested relatively higher imprint stability in the human equivalents. Identification of 202 heterozygous loci allowed us to examine the allelic expression of 22 imprinted genes in 22 human embryonic stem cell lines. Half of the genes examined (IPW, H19, MEG3, MEST isoforms 1 and 2, PEG10, MESTIT1, NESP55, ATP10A, PHLDA2, IGF2) showed variable allelic expression between lines, indicating vulnerability to disrupted imprinting. However, seven genes showed consistent monoallelic expression (NDN, MAGEL2, SNRPN, PEG3, KCNQ1, KCNQ1OT1, CDKN1C). Furthermore, four genes known to be monoallelic or to exhibit polymorphic imprinting in later-developing human tissues (TP73, IGF2R, WT1, SLC22A18) were always biallelic in hESCs. MEST isoform 1, PEG10, and NESP55 showed an association between the variability observed in interline allelic expression status and the DNA methylation of previously identified regulatory regions. Our results demonstrate gene-specific differences in the stability of imprinted loci in human embryonic stem cells and identify disrupted DNA methylation as one potential mechanism. We conclude the prudence of including comprehensive imprinting analysis in the continued characterization of human embryonic stem cell lines.
authors.affiliation: Wolfson Centre for Stem Cells, Tissue Engineering and Modelling (STEM), University of Nottingham, Centre for Biomolecular Sciences, Nottingham NG7 2RD, United Kingdom.
authors.forename: Kee-Pyo
authors.initials: KP
authors.lastname: Kim
authors.forename: Alexandra
authors.initials: A
authors.lastname: Thurston
authors.forename: Christine
authors.initials: C
authors.lastname: Mummery
authors.forename: Dorien
authors.initials: D
authors.lastname: Ward-van Oostwaard
authors.forename: Helen
authors.initials: H
authors.lastname: Priddle
authors.forename: Cinzia
authors.initials: C
authors.lastname: Allegrucci
authors.forename: Chris
authors.initials: C
authors.lastname: Denning
authors.forename: Lorraine
authors.initials: L
authors.lastname: Young
mesh_terms: D000483:Alleles; D000818:Animals; D018236:Carcinoma, Embryonal / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D019175:DNA Methylation; D053595:Embryonic Stem Cells / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D014644:Genetic Variation; D018392:Genomic Imprinting / Q000502:physiology; D006801:Humans; D008297:Male; D051379:Mice