Publication Date:
2001-08-11
Description:
Cloning of mammals by nuclear transfer (NT) results in gestational or neonatal failure with at most a few percent of manipulated embryos resulting in live births. Many of those that survive to term succumb to a variety of abnormalities that are likely due to inappropriate epigenetic reprogramming. Cloned embryos derived from donors, such as embryonic stem cells, that may require little or no reprogramming of early developmental genes develop substantially better beyond implantation than NT clones derived from somatic cells. Although recent experiments have demonstrated normal reprogramming of telomere length and X chromosome inactivation, epigenetic information established during gametogenesis, such as gametic imprints, cannot be restored after nuclear transfer. Survival of cloned animals to birth and beyond, despite substantial transcriptional dysregulation, is consistent with mammalian development being rather tolerant to epigenetic abnormalities, with lethality resulting only beyond a threshold of faulty gene reprogramming encompassing multiple loci.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rideout , W M 3rd -- Eggan, K -- Jaenisch, R -- New York, N.Y. -- Science. 2001 Aug 10;293(5532):1093-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research and, Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11498580" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Cell Differentiation
;
Cell Nucleus/*genetics/metabolism
;
*Cloning, Organism
;
DNA Methylation
;
Dosage Compensation, Genetic
;
Embryo, Mammalian/cytology/*physiology
;
*Embryo, Nonmammalian
;
*Embryonic and Fetal Development
;
Female
;
Gametogenesis
;
*Gene Expression Regulation, Developmental
;
Genomic Imprinting
;
Germ Cells/cytology/physiology
;
Male
;
Nuclear Transfer Techniques
;
Phenotype
;
Stem Cells/cytology/physiology
;
Telomere/physiology/ultrastructure
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
