%0 Journal Article %A HIROKI KONDO %A YOHEI SHIMONO %A JUNKO MUKOHYAMA %A YASUTERU TANAKA %A NAOKI SHIBUYA %A HIRONOBU MINAMI %A YOSHIHIRO KAKEJI %A AKIRA SUZUKI %T Discordance of MCM7 mRNA and its Intronic MicroRNA Levels Under Hypoxia %D 2017 %J Anticancer Research %P 3885-3890 %V 37 %N 7 %X Background: Intronic microRNAs (miRNAs) are considered to be transcribed using their host gene promoter. However, about one third of intronic miRNAs are predicted to have independent promoter elements. Materials and Methods: Human breast cancer cells were cultured under normoxia or hypoxia, and expression levels of intronic miR-106b-25 cluster miRNAs and their host gene minichromosome maintenance complex component 7 (MCM7) transcripts were analyzed by semi-quantitative polymerase chain reaction. The putative promoter element of miR-106b-25 cluster was analyzed by chromatin immunoprecipitation and luciferase assays. Results: Exposure to hypoxia reduced the expression of MCM7 mRNA and a primary transcript of miR-106b-25 cluster, but did not affect that of mature miRNAs. The putative promoter element of miR-106b-25 cluster was not bound by hypoxia-inducible factor 1-alpha (HIF1-α), and was not activated under hypoxia. Conclusion: Maintenance of miR-106b-25 cluster miRNA levels under hypoxia was not caused by the activation of an independent promoter element. %U https://ar.iiarjournals.org/content/anticanres/37/7/3885.full.pdf