A conserved imprinting control region at the HYMAI/ZAC domain is implicated in transient neonatal diabetes mellitus

• Published in: Human molecular genetics Vol. 10; no. 14; pp. 1475 - 1483
• Main Authors: ARIMA, Takahiro, DREWELL, Robert A, ARNEY, Katharine L, INOUE, Jun, MAKITA, Yoshio, HATA, Akira, OSHIMURA, Mitsuo, WAKE, Norio, SURANI, M. Azim
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2001
• Subjects: Alleles; Animals; Biological and medical sciences; chromosome 6; Chromosomes, Human, Pair 6 - genetics; Classical genetics, quantitative genetics, hybrids; Conserved Sequence; CpG Islands - genetics; Diabetes Mellitus - genetics; Diabetes. Impaired glucose tolerance; DNA Methylation; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Fundamental and applied biological sciences. Psychology; Gene Silencing; Genes, Reporter; Genetics of eukaryotes. Biological and molecular evolution; Genomic Imprinting; HeLa Cells; Human; Humans; HYMAI gene; In Vitro Techniques; Male; Medical sciences; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Polymerase Chain Reaction; Promoter Regions, Genetic; Sequence Analysis, DNA; Transcription, Genetic; Transfection; Vertebrata; ZAC gene; Endocrinopathy; Human; Genome organization; Diabetes mellitus; Rodentia; Chromosome C6; Gene expression; Genomic imprinting; Case study; Vertebrata; Mammalia; Mouse; Methylation
• ISSN: 0964-6906; 1460-2083; 1460-2083
• DOI: 10.1093/hmg/10.14.1475

Transient neonatal diabetes mellitus (TNDM) is associated with intra-uterine growth retardation, dehydration and a lack of insulin. Some TNDM patients exhibit paternal uniparental disomy (UPD) of chromosome 6q24, where at least two imprinted genes, HYMAI and ZAC, have so far been characterized. Here we show that the differentially methylated CpG island that partially overlaps mZac1 and mHymai at the syntenic mouse locus is a likely imprinting control region (ICR) for the approximately 120--200 kb domain. The region is unmethylated in sperm but probably methylated in oocytes, a difference that persists between parental alleles throughout pre- and post-implantation development. We also show that within this ICR, there is a region that exhibits a high degree of homology between mouse and human. Using a reporter expression assay, we demonstrate that this conserved region acts as a strong transcriptional repressor when methylated. Finally, we provide in vivo evidence that in the majority of TNDM patients with a normal karyotype, there is a loss of methylation within the highly homologous region. We propose that this ICR regulates expression of imprinted genes within the domain; epigenetic or genetic mutations of this region probably result in TNDM, possibly by affecting expression of ZAC in the pancreas and/or the pituitary.