Etoposide induces nuclear re-localisation of AID.

During B cell activation, the DNA lesions that initiate somatic hypermutation and class switch recombination are introduced by activation-induced cytidine deaminase (AID). AID is a highly mutagenic protein that is maintained in the cytoplasm at steady state, however AID is shuttled across the nuclea...

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Main Authors: Laurens J Lambert, Simon Walker, Jack Feltham, Heather J Lee, Wolf Reik, Jonathan Houseley
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3852760?pdf=render
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author Laurens J Lambert
Simon Walker
Jack Feltham
Heather J Lee
Wolf Reik
Jonathan Houseley
author_facet Laurens J Lambert
Simon Walker
Jack Feltham
Heather J Lee
Wolf Reik
Jonathan Houseley
author_sort Laurens J Lambert
collection DOAJ
description During B cell activation, the DNA lesions that initiate somatic hypermutation and class switch recombination are introduced by activation-induced cytidine deaminase (AID). AID is a highly mutagenic protein that is maintained in the cytoplasm at steady state, however AID is shuttled across the nuclear membrane and the protein transiently present in the nucleus appears sufficient for targeted alteration of immunoglobulin loci. AID has been implicated in epigenetic reprogramming in primordial germ cells and cell fusions and in induced pluripotent stem cells (iPS cells), however AID expression in non-B cells is very low. We hypothesised that epigenetic reprogramming would require a pathway that instigates prolonged nuclear residence of AID. Here we show that AID is completely re-localised to the nucleus during drug withdrawal following etoposide treatment, in the period in which double strand breaks (DSBs) are repaired. Re-localisation occurs 2-6 hours after etoposide treatment, and AID remains in the nucleus for 10 or more hours, during which time cells remain live and motile. Re-localisation is cell-cycle dependent and is only observed in G2. Analysis of DSB dynamics shows that AID is re-localised in response to etoposide treatment, however re-localisation occurs substantially after DSB formation and the levels of re-localisation do not correlate with γH2AX levels. We conclude that DSB formation initiates a slow-acting pathway which allows stable long-term nuclear localisation of AID, and that such a pathway may enable AID-induced DNA demethylation during epigenetic reprogramming.
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spelling doaj.art-ad401a9f4b394d67ac9c6b8e49564fd12022-12-22T01:15:23ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01812e8211010.1371/journal.pone.0082110Etoposide induces nuclear re-localisation of AID.Laurens J LambertSimon WalkerJack FelthamHeather J LeeWolf ReikJonathan HouseleyDuring B cell activation, the DNA lesions that initiate somatic hypermutation and class switch recombination are introduced by activation-induced cytidine deaminase (AID). AID is a highly mutagenic protein that is maintained in the cytoplasm at steady state, however AID is shuttled across the nuclear membrane and the protein transiently present in the nucleus appears sufficient for targeted alteration of immunoglobulin loci. AID has been implicated in epigenetic reprogramming in primordial germ cells and cell fusions and in induced pluripotent stem cells (iPS cells), however AID expression in non-B cells is very low. We hypothesised that epigenetic reprogramming would require a pathway that instigates prolonged nuclear residence of AID. Here we show that AID is completely re-localised to the nucleus during drug withdrawal following etoposide treatment, in the period in which double strand breaks (DSBs) are repaired. Re-localisation occurs 2-6 hours after etoposide treatment, and AID remains in the nucleus for 10 or more hours, during which time cells remain live and motile. Re-localisation is cell-cycle dependent and is only observed in G2. Analysis of DSB dynamics shows that AID is re-localised in response to etoposide treatment, however re-localisation occurs substantially after DSB formation and the levels of re-localisation do not correlate with γH2AX levels. We conclude that DSB formation initiates a slow-acting pathway which allows stable long-term nuclear localisation of AID, and that such a pathway may enable AID-induced DNA demethylation during epigenetic reprogramming.http://europepmc.org/articles/PMC3852760?pdf=render
spellingShingle Laurens J Lambert
Simon Walker
Jack Feltham
Heather J Lee
Wolf Reik
Jonathan Houseley
Etoposide induces nuclear re-localisation of AID.
PLoS ONE
title Etoposide induces nuclear re-localisation of AID.
title_full Etoposide induces nuclear re-localisation of AID.
title_fullStr Etoposide induces nuclear re-localisation of AID.
title_full_unstemmed Etoposide induces nuclear re-localisation of AID.
title_short Etoposide induces nuclear re-localisation of AID.
title_sort etoposide induces nuclear re localisation of aid
url http://europepmc.org/articles/PMC3852760?pdf=render
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