International Mammalian Genome Society

logo18th International Mouse Genome Conference

17-22 October 2004, Seattle, USA


Suzuki T 1, Furuumi H 2, Hashimoto M 3, Kyouno S 4, Nagashima A 1, Kumaki K 2, Kaneda H 1, Gondo Y 5, Noda T 1, Wakana S 1, Ishino F 4, Sasaki H 2, Shiroishi T 1

1 Mouse Functional Genomics Research Group, Genomics Science Center (GSC), RIKEN Yokohama Institute, Yokohama, Japan, 2 Department of Integrated Genetics, National Institute of Genetics, Mishima, Japan, 3 Gene Research Center, Tokyo Institute of Technology, Yokohama, Japan, 4 Department of Epigenetics, Medical Research Center, Tokyo Medical and Dental University, Tokyo, Japan, 5 Population and Quantitative Genomics Team, GSC, RIKEN, Yokohama, Japan

Genomic imprinting is epigenetic regulation of gene expression depending on parental origin of the genes in mammals. In order to detect and identify novel genes involved in the initiation of the genomic imprinting, we have established a screening system for mutants that show impaired genomic imprinting in the RIKEN mouse ENU-mutagenesis program. In our screening, we measure methylation levels of imprinted genes in the mature gametes using methylation-sensitive enzymes or the COBRA (combined bisulfite restriction analysis). Both of non-methylated and re-methylated imprinted genes are analyzed for one individual to detect the mutants that show aberrant imprinting in the two stages: erasure of parental imprints and re-establishment of sex-different imprints. In this system, we can constantly assay the methylation levels of the imprinted genes using approximately 20 gametes originated from one individual.

Since September 2002, we have tested the phenotypes about 1,100 males for dominant screening, and 20 males and 300 females for recessive screening. Several individuals showed abnormal methylation patterns of the imprinted genes in the gametes. These results indicate efficacy of our screening system. We report the current results of the screening and the several phenodeviants that show abnormal methylation patterns.

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