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Stem Cell Related Patent Number US6960434
| Title: | Methods for assaying gene imprinting and methylated CpG islands | | Inventors: | Feinberg, Andrew P.; Cleveland, OH, USA
Strichman-Almashanu, Liora; Baltimore, MD, USA
Jiang, Shan; Trumbull, CT, USA | | Summary: | Herein are described methods of forming embryonic germ cells and assaying genetic imprinting. Further described are the methods of genetic imprinting themselves, as a parent of origin-dependent gene silencing that involves the marking of alleles in the germline and differential expression in somatic cells of the offspring. Disclosed herein are methods by which imprinted genes and abnormal imprinting have been implicated in developmental, human disease, and embryonic stem cell transplantation. The authors claim to have established a model system for genomic imprinting using pluripotent 8.5 d.p.c. mouse embryonic germ (EG) cell lines derived from an interspecific cross, by which they report that allele-specific imprinted gene expression has been lost in the cells. Further disclosed are results expressing partial restoration of allele-specific silencing which can occur for some imprinted genes after in vitro differentiation of EG cells into somatic cell lineages, indicating the presence of a gametic memory that is separable from allele-specific gene silencing. Also described is the identification of a methylome of methylated CpG islands throughout the genome. Applications are provided, such as in a model system to study genetic or genomic imprinting. | | Abstract: | Genomic imprinting is a parent of origin-dependent gene silencing that involves marking of alleles in the germline and differential expression in somatic cells of the offspring. Imprinted genes and abnormal imprinting have been implicated in development, human disease, and embryonic stem cell transplantation. We have established a model system for genomic imprinting using pluripotent 8.5 d.p.c. mouse embryonic germ (EG) cell lines derived from an interspecific cross. We find that allele-specific imprinted gene expression has been lost in these cells. However, partial restoration of allele-specific silencing can occur for some imprinted genes after in vitro differentiation of EG cells into somatic cell lineages, indicating the presence of a gametic memory that is separable from allele-specific gene silencing. We have also generated a library containing most methylated CpG islands. A subset of these clones was analyzed and revealed a subdivision of methylated CpG islands into 4 distinct subtypes: CpG islands belonging to high copy number repeat families; unique CpG islands methylated in all tissues; unique methylated CpG islands that are unmethylated in the paternal germline; and unique CpG islands methylated in tumors. This approach identifies a methylome of methylated CpG islands throughout the genome. | | US Patent Website: | Click Here for Full Text of Patent | | Title Number: | US6960434 | | Application Number: | US2001000861893 | | Date Filed: | 22/05/2001 | | Date Published: | 01/11/2005 | | Assignee: | The Johns Hopkins University, Baltimore, MD, USA |
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