title: DNA hypomethylation of individual sequences in aborted cloned bovine fetuses.
abstract: Cloned bovines have a much higher abortion rate than those derived in vivo. Available evidence indicates that inappropriate epigenetic reprogramming of donor nuclei is the primary cause of cloning failure. To gain a better understanding of the DNA methylation changes associated with the high abortion rate of cloned bovines, we examined the DNA methylation status of a repeated sequence (satellite I) and the promoter regions of two single-copy genes (interleukin 3/cytokeratin) in aborted cloned fetuses, aborted fetuses derived from artificial insemination (AI), cloned adults and AI adults by bisulfite sequencing and restriction enzyme analysis. Two of four aborted cloned fetuses show very low methylation levels in the two single-copy gene promoter regions. One of the two fetuses also showed undermethylated status in the satellite I sequence. The other two aborted cloned fetuses have similar methylation levels to those of aborted AI fetuses. However, no difference in methylation was observed between cloned adults and AI adults. Our results demonstrate for the first time the undermethylated status of individual sequences in aborted cloned fetuses. These findings suggest that aberrant DNA methylation may contribute to the developmental failure of cloned bovine fetuses.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Science, Beijing 100080, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Zhang
authors.forename: Jing-He
authors.initials: JH
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Hou
authors.forename: Heide
authors.initials: H
authors.lastname: Schatten
authors.forename: Da-Yuan
authors.initials: DY
authors.lastname: Chen
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Sun
mesh_terms: D037881:Aborted Fetus / Q000737:chemistry*; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004247:DNA / Q000032:analysis / Q000378:metabolism*; D019175:DNA Methylation; D004276:DNA, Satellite / Q000235:genetics / Q000378:metabolism; D005260:Female; D007377:Interleukin-3 / Q000235:genetics / Q000378:metabolism; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000502:physiology*
chemical_list: D004276:DNA, Satellite; D007377:Interleukin-3; D007633:Keratins; D004247:DNA