TY - JOUR
T1 - Promoter methylation confers kidney-specific expression of the Klotho gene
AU - Azuma, Masahiro
AU - Koyama, Daisuke
AU - Kikuchi, Jiro
AU - Yoshizawa, Hiromichi
AU - Thasinas, Dissayabutra
AU - Shiizaki, Kazuhiro
AU - Kuro-O, Makoto
AU - Furukawa, Yusuke
AU - Kusano, Eiji
PY - 2012/10
Y1 - 2012/10
N2 - The aging suppressor geneKlotho is predominantly expressed in the kidney irrespective of species. Because Klotho protein is an essential component of an endocrine axis that regulates renal phosphate handling, the kidney-specific expression is biologically relevant; however, little is known about its underlying mechanisms. Here we provide in vitro and in vivo evidence indicating that promoter methylation restricts the expression of the Klotho gene in the kidney. Based on evolutionary conservation and histone methylation patterns, the region up to - 1200 bp was defined as a major promoter element of the human Klotho gene. This region displayed promoter activity equally in Klotho-expressing and -nonexpressing cells in transient reporter assays, but the activity was reduced to ∼20% when the constructs were integrated into the chromatin in the latter. Both endogenous and transfected Klotho promoters were 30-40% methylated in Klotho-nonexpressing cells, but unmethylated in Klotho-expressing renal tubular cells. DNA demethylating agents increased Klotho expression 1.5- to 3.0-fold in nonexpressing cells and restored the activity of silenced reporter constructs. Finally, we demonstrated that a severe hypomorphic allele of Klotho had aberrant CpG methylation in kl/kl mice. These findings might be useful in therapeutic intervention for accelerated aging and several complications caused by Klotho downregulation.
AB - The aging suppressor geneKlotho is predominantly expressed in the kidney irrespective of species. Because Klotho protein is an essential component of an endocrine axis that regulates renal phosphate handling, the kidney-specific expression is biologically relevant; however, little is known about its underlying mechanisms. Here we provide in vitro and in vivo evidence indicating that promoter methylation restricts the expression of the Klotho gene in the kidney. Based on evolutionary conservation and histone methylation patterns, the region up to - 1200 bp was defined as a major promoter element of the human Klotho gene. This region displayed promoter activity equally in Klotho-expressing and -nonexpressing cells in transient reporter assays, but the activity was reduced to ∼20% when the constructs were integrated into the chromatin in the latter. Both endogenous and transfected Klotho promoters were 30-40% methylated in Klotho-nonexpressing cells, but unmethylated in Klotho-expressing renal tubular cells. DNA demethylating agents increased Klotho expression 1.5- to 3.0-fold in nonexpressing cells and restored the activity of silenced reporter constructs. Finally, we demonstrated that a severe hypomorphic allele of Klotho had aberrant CpG methylation in kl/kl mice. These findings might be useful in therapeutic intervention for accelerated aging and several complications caused by Klotho downregulation.
KW - Aging
KW - CpG island
KW - Kl/kl mouse
KW - VISTA analysis
UR - http://www.scopus.com/inward/record.url?scp=84868150022&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84868150022&partnerID=8YFLogxK
U2 - 10.1096/fj.12-211631
DO - 10.1096/fj.12-211631
M3 - Article
C2 - 22782974
AN - SCOPUS:84868150022
SN - 0892-6638
VL - 26
SP - 4264
EP - 4274
JO - FASEB Journal
JF - FASEB Journal
IS - 10
ER -