J. Biochem. 128,847-853 (2000) A Novel Imprinted Gene, KCNQ1DN, within the WT2 Critical Region of Human Chromosome Ilpl5.5 and Its Reduced Expression in Wilms'

WT2 is denned by a maternal-specific loss of heterozygosity on human chromosome Ilpl5.5 in Wilms ' and other embryonal tumors. Therefore, the imprinted genes in this region are candidates for involvement in Wilms ' tumorigenesis. We now report a novel imprinted gene, KCNQ1DN (KCNQ1 downstream neighbor). This gene is located between p57KIP2 and KvLQTl (KCNQ1) of Ilpl5.5 within the WT2 critical region. KCNQ1DN is imprinted and expressed from the maternal allele. We examined the ex-pression of KCNQ1DN in Wihns ' tumors. Seven of eighteen (39%) samples showed no ex-pression. In contrast, other maternal imprinted genes in this region, including p57laP2, IMPT1, and IPL exhibited almost normal expression in these samples, although some samples expressed IGF2 biallelically. These results suggest that KCNQ1DN existing far from the H19/IGF2 region may play some role in Wilms ' tumorigenesis along with IGF2. Key words: CpG island, imprinted genes, genomic imprinting, KCNQ1DN, Wihns' tumors. Genomic imprinting is an epigenetic modification that can lead to parental-allele-specific expression of genes, whic