Demethylation of the coding region triggers the activation of the human testis-specific PDHA2 gene in somatic tissues.
Human PDHA2 is a testis-specific gene that codes for the E(1)α subunit of Pyruvate Dehydrogenase Complex (PDC), a crucial enzyme system in cell energy metabolism. Since activation of the PDHA2 gene in somatic cells could be a new therapeutic approach for PDC deficiency, we aimed to identify the regulatory mechanisms underlying the human PDHA2 gene expression. Functional deletion studies revealed that the -122 to -6 promoter region is indispensable for basal expression of this TATA-less promoter, and suggested a role of an epigenetic program in the control of PDHA2 gene expression. Indeed, treatment of SH-SY5Y cells with the hypomethylating agent 5-Aza-2'-deoxycytidine (DAC) promoted the reactivation of the PDHA2 gene, by inducing the recruitment of the RNA polymerase II to the proximal promoter region and the consequent increase in PDHA2 mRNA levels. Bisulfite sequencing analysis revealed that DAC treatment induced a significant demethylation of the CpG island II (nucleotides +197 to +460) in PDHA2 coding region, while the promoter region remained highly methylated. Taken together with our previous results that show an in vivo correlation between PDHA2 expression and the demethylation of the CpG island II in testis germ cells, the present results show that internal methylation of the PDHA2 gene plays a part in its repression in somatic cells. In conclusion, our data support the novel finding that methylation of the PDHA2 coding region can inhibit gene transcription. This represents a key mechanism for absence of PDHA2 expression in somatic cells and a target for PDC therapy.
Research Institute for Medicines and Pharmaceutical Sciences, iMed.UL, Lisbon, Portugal.
Ana
A
Pinheiro
Maria João
MJ
Nunes
Inês
I
Milagre
Elsa
E
Rodrigues
Maria João
MJ
Silva
Isabel Tavares
IT
de Almeida
Isabel
I
Rivera
D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D000077209:Decitabine; D044127:Epigenesis, Genetic / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics*; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D030481:Pyruvate Dehydrogenase (Lipoamide) / Q000235:genetics* / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013737:Testis / Q000187:drug effects / Q000201:enzymology*; D024363:Transcription Initiation Site / Q000187:drug effects
D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D000077209:Decitabine; C550671:PDHA2 protein, human; D030481:Pyruvate Dehydrogenase (Lipoamide); D012319:RNA Polymerase II; D001374:Azacitidine