Understanding the role of B-Myb during DNA replication in embryonic stem cells

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Blakemore, Daniel John ORCID: https://orcid.org/0000-0003-4449-4754 (2020). Understanding the role of B-Myb during DNA replication in embryonic stem cells. University of Birmingham. Ph.D.

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Abstract

The acquisition of genetic lesions represents a major threat to embryonic stem cell (ESC) function due to the potential passage of mutations onto the whole embryo. Owing to this, stem cells have a superior capacity to prevent and repair genetic lesions, although, the mechanisms responsible remain elusive. The transcription factor B-Myb, for which deregulation is implicated in tumourigenesis, is found substantially elevated in ESCs. Through the generation of B-myb mutant ESCs (B-mybΔ/Δ), this study uncovers an important role for B-Myb in control of the replication programme, with its loss resulting in; replication slowdown, elevated origin firing, replication factory activation, cell cycle deregulation and DNA damage accumulation. Further investigation revealed that the activity of CDK1, associated with control replication initiation, was elevated in the B-mybΔ/Δ, moreover, inhibition of replication initiation through targeting CDK1 or Cdc7 resulted in a substantial rescue of the replication stress. In addition, inhibition of ATM dependent signalling was epistatic with B-Myb loss for the replication stress phenotype, suggesting B-Myb exerts its role through the DNA damage response. Transcriptome analysis of the B-mybΔ/Δ was performed revealing changes in proliferation associated pathways and in the expression of chromatin modifiers. Overall, this study proposes an ATM-CDK-B-Myb axis important for control of cell cycle progression and DNA replication in ESCs.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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