title: Sp1 is a competitive endogenous RNA of Klf4 during odontoblast differentiation.
abstract: Our previous studies have demonstrated that KLF4 is a critical transcription factor that promotes the odontoblastic differentiation of dental papilla cells. Klf4 mRNA was found to be regulated by multiple microRNAs (miRNAs). Competitive endogenous RNAs (ceRNAs) are a group of transcripts post-transcriptionally regulating each other by competing for their common miRNAs. However, the regulation of Klf4 by ceRNAs in odontoblastic differentiation remains unknown. In this study, we predicted a group of potential Klf4 ceRNAs with bioinformatics approach, and examined the expression of Klf4 and five interested potential ceRNAs including Sp1 using real-time PCR during odontoblastic differentiation of mDPC6T. The expression levels of both Sp1 and Klf4 were significantly upregulated during this process. In situ hybridization verified that Sp1 was co-expressed with Klf4 in the differentiating and the mature odontoblasts in vivo. Knockdown of Sp1 using siRNA resulted in a significant reduction of Klf4 and vice visa. This interaction was further confirmed to be miRNA dependent. Common miRNAs of Klf4 and Sp1 were predicted, among which miR-7a, miR-29b and miR-135a were able to downregulate both Klf4 and Sp1 expression after their separate overexpression in the mDPC6T cells. Dual luciferase assays showed that these miRNAs separately regulated the 3'UTRs of both Klf4 and Sp1, and the down-regulation of Klf4 3 'UTR by Sp1 siRNA was abolished when these three miRNAs' binding sites were mutated in the Klf4 3 'UTR. Therefore, our results indicate that Sp1 functions as a ceRNA of Klf4 during odontoblastic differentiation through competing for miR-7a, miR-29b and miR-135a.
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Lin
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Shuchen
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Huangheng
authors.initials: H
authors.lastname: Tao
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China. Electronic address: yuanguohua@whu.edu.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Yuan
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China. Electronic address: zhichen@whu.edu.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D012313:RNA / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D060888:Real-Time Polymerase Chain Reaction; D051703:Sp Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D035683:MicroRNAs; D051703:Sp Transcription Factors; D012313:RNA
keywords: Differentiation; Klf4; Odontoblast; Sp1; ceRNAs; miRNA response elements; microRNAs