Transcription-induced formation of extrachromosomal DNA during yeast ageing

Hull, Ryan M. and King, Michelle and Pizza, Grazia and Krueger, Felix and Vergara, Xabier and Houseley, Jonathan and Gresham, David (2019) Transcription-induced formation of extrachromosomal DNA during yeast ageing. PLOS Biology, 17 (12). e3000471. ISSN 1545-7885

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Abstract

Extrachromosomal circular DNA (eccDNA) facilitates adaptive evolution by allowing rapid and extensive gene copy number variation and is implicated in the pathology of cancer and ageing. Here, we demonstrate that yeast aged under environmental copper accumulate high levels of eccDNA containing the copper-resistance gene CUP1. Transcription of the tandemly repeated CUP1 gene causes CUP1 eccDNA accumulation, which occurs in the absence of phenotypic selection. We have developed a sensitive and quantitative eccDNA sequencing pipeline that reveals CUP1 eccDNA accumulation on copper exposure to be exquisitely site specific, with no other detectable changes across the eccDNA complement. eccDNA forms de novo from the CUP1 locus through processing of DNA double-strand breaks (DSBs) by Sae2, Mre11 and Mus81, and genome-wide analyses show that other protein coding eccDNA species in aged yeast share a similar biogenesis pathway. Although abundant, we find that CUP1 eccDNA does not replicate efficiently, and high-copy numbers in aged cells arise through frequent formation events combined with asymmetric DNA segregation. The transcriptional stimulation of CUP1 eccDNA formation shows that age-linked genetic change varies with transcription pattern, resulting in gene copy number profiles tailored by environment.

Item Type: Article
Subjects: Research Scholar Guardian > Biological Science
Depositing User: Unnamed user with email support@scholarguardian.com
Date Deposited: 03 Feb 2023 10:57
Last Modified: 01 Jan 2024 12:31
URI: http://science.sdpublishers.org/id/eprint/73

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