| Research Abstract |
We previously specified the gene p57KIP2 as a responsible gene for Beckwith-Wiedemann syndrome. This time, we further collected the patients. Over all, flinty one patients were collected, analized and mutaitons were found in ten patients, indicating the frequency of 11%. QT domain of p57KIP2 gen was always deleted in all of the mutant. In order to know a function of the mutation in a cellular level, we first examined the cellular localization of this gene product because we observed a nuclear localization signal in a C-terminus of this protein. In addition, we also analized an inhibitory activity of the phosphorylation in vitro using the product which was expressed in E.coli. The result showed the nuclear localization of the wild type, ut two mutants, patient 6 and 8, both could not enter into the nucleus and remained in the cytoplasm, suggesting the nuclear localization might be inhibited in all patients. Inhibition of the phosphorylation was not observed in the patient 6 whose CDK inhibitory domain is truncated, but did observed in the patient S whose inhibitory domain is left intact.
We searched the mutation of p57K1P2 and the neighboring genes-MPT1, 1PL and ORCTL2S.in the embryonal tumor including Wilms tumor, hepatoblastoma, rabdomyosarcoma and adrenocortical carcinoma. 41 cases were analyzed. No deletion and rearrangement of the p57KIP2 was found in Wilms tumor and then tumors are directly sequenced in 50 cases, but no mutation found at all. We found, however, one case of missense mutation in Wilms tumor and each one case of LOR in hepatoblastoma and adrenocortical carcinoma in ORCTL2S gene.
We analyzed the methylation status of the surrounding area of p57KIP2. Ten kilobase of the region was examined using methylation-sensitive enzyme. No methylation was found in the human genome at all, although this gen is imprinted. On the other hand, n paternal methylation was observed in the mouse genome because this gene is expressed maternally.
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