title: Transcriptional gene silencing of dopamine D3 receptor caused by let-7d mimics in immortalized renal proximal tubule cells of rats.
abstract: Transcriptional gene silencing (TGS) induced by synthetic exogenous short interfering RNAs (siRNAs) that are fully complementary to gene promoters has been demonstrated in mammalian cells. However, it remains unclear whether microRNAs (miRNAs), which are endogenous small regulatory RNAs, can also silence gene transcription. We investigated the regulation mechanism of let-7d on dopamine D3 receptor (DRD3) in immortalized renal proximal tubule (RPT) cells of rats, where let-7d has a predicted homologous target site within DRD3 promoter. We found that let-7d mimics repressed DRD3 expression at the transcription level in RPT cells. Let-7d induced DRD3 inhibition via DNA-methyltransferase 1 (DNMT1) and DNA-methyltransferase 3b (DNMT3b) dependent DNA methylation and the inhibition could be abolished by 5'-aza-2'-deoxycytidine (5-aza-dc), a DNA methylation inhibitor. Let-7d induced DRD3 repression was associated with the recruitment of Argonaute 2 (AGO2) protein. Histone 3 lysine 9 dimethylation (H3K9me2) was involved in the let-7d induced DRD3 TGS, indicating the chromatin-level silencing. In conclusion, our results demonstrated that let-7d may induce DRD3 repression in a transcriptional manner by means of DNMTs dependent DNA methylation and histone modification. It is suggested that miRNAs may act as a transcriptional gene regulator via the recognition of the homologous target site within the gene promoter.
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Caiyu
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Duofen
authors.initials: D
authors.lastname: He
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Shi
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Chunjiang
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China.
authors.forename: Xukai
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing, PR China. Electronic address: chunyuzeng01@163.com.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Zeng
mesh_terms: D000818:Animals; D001483:Base Sequence; D002461:Cell Line, Transformed; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D035683:MicroRNAs / Q000737:chemistry / Q000494:pharmacology*; D018716:Molecular Mimicry; D034622:RNA Interference / Q000187:drug effects*; D051381:Rats; D011921:Rats, Inbred WKY; D050637:Receptors, Dopamine D3 / Q000235:genetics*
chemical_list: C548145:MIRNLET7 microRNA, rat; D035683:MicroRNAs; D050637:Receptors, Dopamine D3; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619382:Dnmt1 protein, rat
keywords: DNA methylation; Dopamine D(3) receptor; Let-7d; Transcriptional gene silencing