title: Investigation of microRNA expression and DNA repair gene transcripts in human oocytes and blastocysts.
abstract: OBJECTIVE
  The aim of the study is to investigate the regulation of DNA repair genes by microRNAs (miRNAs). miRNAs are short non-coding RNAs that regulate transcriptional and post-transcriptional gene silencing. Several miRNAs that are expressed during preimplantation embryo development have been shown or are predicted to target genes that regulate cell cycle checkpoints and DNA repair in response to DNA damage.
  
  
  METHODS
  This study compares the expression level of 20 miRNAs and 9 target transcripts involved in DNA repair. The statistical significance of differential miRNA expression between oocytes and blastocysts was determined by t test analysis using the GraphPad Prism v6 software. The possible regulatory roles of miRNAs on their target messenger RNAs (mRNAs) were analysed using a Pearson correlation test.
  
  
  RESULTS
  This study shows for the first time that several miRNAs are expressed in human oocytes and blastocysts that target key genes involved in DNA repair and cell cycle checkpoints. Blastocysts exhibited statistically significant lower expression levels for the majority of miRNAs compared to oocytes (p < 0.05). Correlation analyses showed that there was both inverse and direct association between miRNAs and their target mRNAs.
  
  
  CONCLUSIONS
  miRNAs target many mRNAs including ones involved in DNA repair mechanisms. This study suggests that miRNAs and their target mRNAs involved in DNA repair are expressed in preimplantation embryos. Similar to the miRNAs expressed in adult tissues, these miRNAs seem to have regulatory roles on their target DNA repair mRNAs during preimplantation embryo development.
authors.affiliation: Faculty of Medicine, Medical Genetics Department, Near East University, Yakin Dogu Bulvari, Nicosia, Cyprus. pintulay@gmail.com.|UCL Centre for PGD, Institute for Women's Health, University College London, London, UK. pintulay@gmail.com.
authors.forename: P
authors.initials: P
authors.lastname: Tulay
authors.affiliation: UCL Centre for PGD, Institute for Women's Health, University College London, London, UK.
authors.forename: R P
authors.initials: RP
authors.lastname: Naja
authors.affiliation: UCL Centre for PGD, Institute for Women's Health, University College London, London, UK.
authors.forename: O
authors.initials: O
authors.lastname: Cascales-Roman
authors.affiliation: The Centre for Reproductive and Genetic Health, University College Hospital, The New Wing Eastman Dental Hospital, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Doshi
authors.affiliation: The Centre for Reproductive and Genetic Health, University College Hospital, The New Wing Eastman Dental Hospital, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Serhal
authors.affiliation: UCL Centre for PGD, Institute for Women's Health, University College London, London, UK.
authors.forename: S B
authors.initials: SB
authors.lastname: SenGupta
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism* / Q000502:physiology; D009865:Oocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger
keywords: DNA repair; Expression; Human oocyte and blastocyst; MicroRNA; Preimplantation embryo development