title: Differential regulation of MCM7 and its intronic miRNA cluster miR-106b-25 during megakaryopoiesis induced polyploidy.
abstract: Megakaryocytes exit from mitotic cell cycle and enter a phase of repeated DNA replication without undergoing cell division, in a process termed as endomitosis of which little is known. We studied the expression of a DNA replication licensing factor mini chromosome maintenance protein 7 (MCM7) and its intronic miR-106b-25 cluster during mitotic and endo-mitotic cycles in megakaryocytic cell lines and in vitro cultured megakaryocytes obtained from human cord blood derived CD34(+) cells. Our results show that contrary to mitotic cell cycle, endomitosis proceeds with an un-coupling of the expression of MCM7 and miR-106b-25. This was attributed to the presence of a transcript variant of MCM7 which undergoes nonsense mediated decay (NMD). Additionally, miR-25 which was up regulated during endomitosis was found to promote megakaryopoiesis by inhibiting the expression of PTEN. Our study thus highlights the importance of a transcript variant of MCM7 destined for NMD in the modulation of megakaryopoiesis.
authors.affiliation: a Biophysics and Structural Genomics Division; Saha Institute of Nuclear Physics ; Kolkata , India.
authors.forename: Srijan
authors.initials: S
authors.lastname: Haldar
authors.forename: Anita
authors.initials: A
authors.lastname: Roy
authors.forename: Subrata
authors.initials: S
authors.lastname: Banerjee
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004261:DNA Replication; D005312:Fetal Blood / Q000166:cytology / Q000378:metabolism; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D047468:Immunoprecipitation; D007438:Introns / Q000235:genetics*; D008533:Megakaryocytes / Q000166:cytology / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D018613:Microscopy, Confocal; D064168:Minichromosome Maintenance Complex Component 7 / Q000235:genetics* / Q000378:metabolism; D008938:Mitosis / Q000502:physiology; D059365:Nonsense Mediated mRNA Decay / Q000502:physiology; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D011123:Polyploidy; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015533:Transcriptional Activation
chemical_list: C542541:MIRN106 microRNA, human; C543351:MIRN25 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7
keywords: APC, Allophycocyanin; FACS, Fluorescence Activated Cell Sorting; HPRT, Hypoxanthine PhosphoRibosyl Transferase; MCM7; Nonsense mediated decay; PE, R-phycoerythrin; PTEN; RIPA, Radio immuno precipitation Assay; megakaryopoiesis; miRNA; polyploidy; qRT-PCR, quantitative real time polymerase chain reaction