title: Dot1l deficiency leads to increased intercalated cells and upregulation of V-ATPase B1 in mice.
abstract: The collecting duct in the mammalian kidney consists of principal cells (PCs) and intercalated cells (ICs), which regulate electrolyte/fluid and acid/base balance, respectively. The epigenetic regulators of PC and IC differentiation remain obscure. We previously used Aqp2 and V-ATPase B1B2 to label PCs and ICs, respectively. We found that mice with histone H3 K79 methyltransferase Dot1l disrupted in Aqp2-expressing cells (Dot1l(AC)) vs. Dot1l(f/f) possessed ~20% more ICs coupled with a similar decrease in PCs. Here, we performed multiple double immunofluorescence staining using various PC and IC markers and confirmed that this finding. Both α-IC and β-IC populations were significantly expanded in Dot1l(AC) vs. Dot1l(f/f). These changes are associated with significantly upregulated V-ATPase B1 and B2, but not Aqp2, AE1, and Pendrin. Chromatin immunoprecipitation assay unveiled a significant reduction of Dot1l and H3K79 di-methylation bound at the Atp6v1b1 5' flanking region. Overexpression of Dot1a significantly downregulated a stably-transfected luciferase reporter driven by the Atp6v1b1 promoter in IMCD3 cells. This downregulation was impaired, but not completely abolished when a methyltransferase-dead mutant was overexpressed. Taken together, our data suggest that Dot1l is a new epigenetic regulator of PC and IC differentiation and Atp6v1b1 is a new transcriptional target of Dot1l.
authors.affiliation: Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China; Department of Internal Medicine, University of Texas Medical School at Houston, Houston, TX 77030, USA.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Xiao
authors.affiliation: Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
authors.forename: Lihe
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China.
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Internal Medicine, University of Texas Medical School at Houston, Houston, TX 77030, USA; Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX 77030, USA. Electronic address: Wenzheng.zhang@uth.tmc.edu.
authors.forename: Wenzheng
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism; D051399:Aquaporin 2 / Q000378:metabolism; D051400:Aquaporin 3 / Q000378:metabolism; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism; D007668:Kidney / Q000166:cytology*; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D008780:Methyltransferases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D051399:Aquaporin 2; D006657:Histones; D012333:RNA, Messenger; D051400:Aquaporin 3; C481527:Dot1l protein, mouse; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; C480628:Atp6v1b1 protein, mouse; D025262:Vacuolar Proton-Translocating ATPases; D008239:Lysine
keywords: Conditional knockout; Histone methyltransferase Dot1l; Intercalated cells; Principal cells; V-ATPase