Mechanism of Wnt signaling induced down regulation of mrhl long non-coding RNA in mouse spermatogonial cells

• Published in: Nucleic acids research Vol. 44; no. 1; pp. 387 - 401
• Main Authors: Akhade, Vijay Suresh, Dighe, Shrinivas Nivrutti, Kataruka, Shubhangini, Rao, Manchanahalli R Satyanarayana
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 08.01.2016
• Subjects: Alcohol Oxidoreductases - metabolism; Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors - metabolism; beta Catenin - metabolism; Binding Sites; Biomarkers; Cell Differentiation - genetics; Cell Line; Co-Repressor Proteins - metabolism; DNA-Binding Proteins - metabolism; Down-Regulation; Gene Expression; Gene Expression Regulation; Genes, Reporter; Histones - metabolism; Humans; Male; Mice; Promoter Regions, Genetic; Protein Binding; RNA; RNA, Long Noncoding - genetics; Spermatogonia - cytology; Spermatogonia - metabolism; Transcription Factor 4; Transcription, Genetic; Wnt Signaling Pathway
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkv1023

Long non coding RNAs (lncRNAs) have emerged as important regulators of various biological processes. LncRNAs also behave as response elements or targets of signaling pathway(s) mediating cellular function. Wnt signaling is important in regulating mammalian spermatogenesis. Mrhl RNA negatively regulates canonical Wnt pathway and gets down regulated upon Wnt signaling activation in mouse spermatogonial cells. Also, mrhl RNA regulates expression of genes pertaining to Wnt pathway and spermatogenesis by binding to chromatin. In the present study, we delineate the detailed molecular mechanism of Wnt signaling induced mrhl RNA down regulation in mouse spermatogonial cells. Mrhl RNA has an independent transcription unit and our various experiments like Chromatin Immunoprecipitation (in cell line as well as mouse testis) and shRNA mediated down regulation convincingly show that β-catenin and TCF4, which are the key effector proteins of the Wnt signaling pathway are required for down regulation of mrhl RNA. We have identified Ctbp1 as the co-repressor and its occupancy on mrhl RNA promoter depends on both β-catenin and TCF4. Upon Wnt signaling activation, Ctbp1 mediated histone repression marks increase at the mrhl RNA promoter. We also demonstrate that Wnt signaling induced mrhl RNA down regulation results in an up regulation of various meiotic differentiation marker genes.