TY - JOUR
T1 - A new class of tissue-specifically methylated regions involving entire CpG islands in the mouse
AU - Suzuki, Masako
AU - Sato, Shun
AU - Arai, Yoshikazu
AU - Shinohara, Takashi
AU - Tanaka, Satoshi
AU - Greally, John M.
AU - Hattori, Naka
AU - Shiota, Kunio
PY - 2007/12
Y1 - 2007/12
N2 - CpG islands, which have higher GC content and CpG frequencies compared to the genome as a whole, are generally believed to be unmethylated in tissues except at promoters of genes undergoing X chromosome inactivation or genomic imprinting. Recent studies, however, have shown that CpG islands at promoters of a number of genes contain tissue-dependent, differentially methylated regions (T-DMRs). In general, the tissue-specific methylation is restricted to a part of the promoter CpG island, with hypomethylation of the remaining sequence. In the current study, using comparison between Restriction Landmark Genomic Scanning (RLGS) and in silico RLGS, we identified ten sperm-specific unmethylated Not I sites, T-DMRs located in CpG islands that were hypomethylated in sperm but near-completely methylated in the kidney and brain. Unusually, these T-DMRs involve the whole CpG island at each of these loci. We characterized one of these genes, adenine nucleotide translocator 4 (Ant4), which is expressed in germ cells. Using a promoter assay, we demonstrated that expression of Ant4 gene is controlled by DNA methylation at the CpG island sequences within the promoter region. Ant4 and other sperm-specific hypomethylated loci represent a new class of CpG islands that become completely methylated in different cell lineages. T-DMRs at CpG islands are functionally important gene regulatory elements that may now be categorized into two classes: T-DMRs involving a subregion of the CpG island and those that occupy the whole CpG island.
AB - CpG islands, which have higher GC content and CpG frequencies compared to the genome as a whole, are generally believed to be unmethylated in tissues except at promoters of genes undergoing X chromosome inactivation or genomic imprinting. Recent studies, however, have shown that CpG islands at promoters of a number of genes contain tissue-dependent, differentially methylated regions (T-DMRs). In general, the tissue-specific methylation is restricted to a part of the promoter CpG island, with hypomethylation of the remaining sequence. In the current study, using comparison between Restriction Landmark Genomic Scanning (RLGS) and in silico RLGS, we identified ten sperm-specific unmethylated Not I sites, T-DMRs located in CpG islands that were hypomethylated in sperm but near-completely methylated in the kidney and brain. Unusually, these T-DMRs involve the whole CpG island at each of these loci. We characterized one of these genes, adenine nucleotide translocator 4 (Ant4), which is expressed in germ cells. Using a promoter assay, we demonstrated that expression of Ant4 gene is controlled by DNA methylation at the CpG island sequences within the promoter region. Ant4 and other sperm-specific hypomethylated loci represent a new class of CpG islands that become completely methylated in different cell lineages. T-DMRs at CpG islands are functionally important gene regulatory elements that may now be categorized into two classes: T-DMRs involving a subregion of the CpG island and those that occupy the whole CpG island.
UR - http://www.scopus.com/inward/record.url?scp=36749083455&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36749083455&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2443.2007.01136.x
DO - 10.1111/j.1365-2443.2007.01136.x
M3 - Article
C2 - 18076568
AN - SCOPUS:36749083455
VL - 12
SP - 1305
EP - 1314
JO - Genes to Cells
JF - Genes to Cells
SN - 1356-9597
IS - 12
ER -