Public Defence: Yanjiao Li

MSc Yanjiao Li at Institute of Basic Medical Sciences will be defending the thesis “Single-Cell N6-Methyladenosine (m6A) Mapping in Oocytes and Preimplantation Embryos” for the degree of PhD (Philosophiae Doctor).

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Photo: Yan Zhang.

An electronic copy of the thesis may be ordered from the faculty up to 2 days prior to the public defence. Inquiries regarding the thesis after the public defence must be addressed to the candidate.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Professor Peter Brodersen, University of Copenhagen
  • Second opponent: Professor Eva Sjøttem, UiT The Arctic University of Norway
  • Third member and chair of the evaluation committee: Professor Erik Dissen, University of Oslo

Chair of the Defence

Professor Yvonne Böttcher, University of Oslo

Principal Supervisor

Adjunct Professor Arne Klungland, Faculty of Medicine, University of Oslo


N6-methyladenosine (m6A) is the most prevalent and abundant internal modification in mRNAs. It plays regulatory roles that control gene expression in diverse cellular processes, including RNA transcription, splicing, nuclear export, decay, and translation. Despite the considerable improvements in m6A mapping methodology, the applicability of current methods is limited by the need for large amounts of input materials. In this thesis, we first developed an m6A ultra-low/single-cell MeRIP-seq mapping assay to study transcriptome-wide m6A modification profiles using limited numbers of cells and single cells. We describe the whole protocol in a step-by-step manner. In brief, m6A-containing RNA is immunoprecipitated with an anti-m6A antibody prior to single-tube library construction and sequencing with a high-throughput DNA sequencer, constituting an easy, robust and reliable technique for mapping m6A at the ultra-low/single-cell level. Second, we validated the method by profiling m6A modifications in serial dilutions of poly(A)-selected RNA from mouse liver and demonstrated its utility by assays single zebrafish zygotes, single mouse MII oocytes and mouse blastocysts. Intriguingly, we found that m6A was deposited predominantly on the MTA_Mm retrotransposon in MII oocytes. Third, by applying scMeRIP–seq in mouse oocytes and preimplantation embryos in different stages of development, we investigated the landscapes of m6A in early mammalian development, revealing unique spatiotemporal m6A dynamics that accompany early mammalian development. Collectively, our work opens a new avenue for studying m6A in a single cell and in rare cells in a transcriptome-wide manner.


Additional information

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Published June 14, 2022 10:59 AM - Last modified June 24, 2022 1:16 PM