The splicing regulator PTBP2 interacts with the cytidine deaminase AID and promotes binding of AID to switch-region DNA

Nowak, Urszula; Matthews, Allysia J.; Zheng, Simin; Chaudhuri, Jayanta

doi:10.1038/ni.1977

Cited by 110 publications

(90 citation statements)

References 36 publications

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“…These studies provided compelling reasons to investigate the role of RNA processing during CSR. Recently published studies have implicated components of the RNA splicing machinery complex (CTNNBL1 and PTBP2) as being required for efficient CSR, thereby providing further cause for determining the exact role of RNA splicing in AID activity (Conticello et al 2008;Nowak et al 2011). The role of these factors and RNA splicing in general during SHM has not been thoroughly determined due to the lack of existing RNA splicing-deficient mouse models that can be a source of proliferating GC B cells.…”

Section: Rna Processing Pathways That Regulate Csrmentioning

confidence: 99%

Regulation of AID, the B-cell genome mutator

et al. 2013

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The mechanisms by which B cells somatically engineer their genomes to generate the vast diversity of antibodies required to challenge the nearly infinite number of antigens that immune systems encounter are of tremendous clinical and academic interest. The DNA cytidine deaminase activation-induced deaminase (AID) catalyzes two of these mechanisms: class switch recombination (CSR) and somatic hypermutation (SHM). Recent discoveries indicate a significant promiscuous targeting of this B-cell mutator enzyme genome-wide. Here we discuss the various regulatory elements that control AID activity and prevent AID from inducing genomic instability and thereby initiating oncogenesis.

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Section: Rna Processing Pathways That Regulate Csrmentioning

confidence: 99%

Regulation of AID, the B-cell genome mutator

et al. 2013

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“…While GLT is non-productive due to stop codons in all three reading frames of I-exons, CSR needs I-exon splicing onto C H exons 7 . This might be due to the contribution of the splicing regulator PTBP2 to AID recruitment 8 . Recent evidence also suggested that, during CSR, AID directly recruits MMR and BER factors 2 .…”

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confidence: 99%

Efficient AID targeting of switch regions is not sufficient for optimal class switch recombination

et al. 2015

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Antibody affinity maturation relies on activation-induced cytidine deaminase (AID)-dependent somatic hypermutation (SHM) of immunoglobulin (Ig) loci. Class switch recombination (CSR) can in parallel occur between AID-targeted, transcribed, spliced and repetitive switch (S) regions. AID thus initiates not only mutations but also double-strand breaks (DSBs). What governs the choice between those two outcomes remains uncertain. Here we explore whether insertion of transcribed intronic S regions in a locus (Igk) strongly recruiting AID is sufficient for efficient CSR. Although strongly targeted by AID and carrying internal deletions, the knocked-in S regions only undergo rare CSR-like events. This model confirms S regions as exquisite SHM targets, extending AID activity far from transcription initiation sites, and shows that such spliced and repetitive AID targets are not sufficient by themselves for CSR. Beyond transcription and AID recruitment, additional IgH elements are thus needed for CSR, restricting this hazardous gene remodelling to IgH loci.

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“…A number of cofactors have been identified by a combination of genetic and proteomic approaches, which suggest that AID synchronizes with other broadly important cellular pathways including, but not limited to, RNA splicing and processing (9, 10), cellular trafficking (11)(12)(13)(14), and transcription/RNA polymerase stalling (8,(15)(16)(17); however, a concise picture of the players involved in the AID reaction and the sequence of events remains unclear. Here, we use our solubility-based screening technique to identify a unique interacting partner for AID, RING finger protein 126 (RNF126).…”

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confidence: 99%

Solubility-based genetic screen identifies RING finger protein 126 as an E3 ligase for activation-induced cytidine deaminase

Delker¹,

Zhou²,

Strikoudis³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Protein-protein interactions are typically identified by either biochemical purification coupled to mass spectrometry or genetic approaches exemplified by the yeast two-hybrid assay; however, neither assay works well for the identification of cofactors for poorly soluble proteins. Solubility of a poorly soluble protein is thought to increase upon cofactor binding, possibly by masking otherwise exposed hydrophobic domains. We have exploited this notion to develop a high-throughput genetic screen to identify interacting partners of an insoluble protein fused to chloramphenicol acetyltransferase by monitoring the survival of bacteria in the presence of a drug. In addition to presenting proof-of-principle experiments, we apply this screen to activation-induced cytidine deaminase (AID), a poorly soluble protein that is essential for antibody diversification. We identify a unique cofactor, RING finger protein 126 (RNF126), verify its interaction by traditional techniques, and show that it has functional consequences as RNF126 is able to ubiquitylate AID. Our results underpin the value of this screening technique and suggest a unique form of AID regulation involving RNF126 and ubiquitylation.ubiquitin | immunology | lymphocyte M ost large-scale protein-protein interaction data published to date has been produced with yeast two-hybrid assays (1-3) and in vivo pull-down approaches followed by mass spectrometry to identify proteins that coprecipitate with the protein of interest. Although these purification methods were first developed for small-scale protein identification experiments, they have been successfully adapted for use in genome-wide proteomics studies (4-6). Proteins that are poorly soluble or insoluble when ectopically expressed are least amenable to characterization using these tools. Improper folding or exposure of hydrophobic domains can result in insolubility when proteins are expressed individually; however, soluble complexes can form upon coexpression of a native partner. Based on this idea, we have devised a high-throughput protein-protein interaction screen, which involves the coexpression and cofolding of two proteins: an unknown protein expressed from a cDNA library and a known, insoluble "bait" fused to a protein that confers antibiotic resistance. Thus, solubility is directly linked to a traceable marker. We apply this technique to identify cofactors for activation-induced cytidine deaminase (AID), an enzyme that deaminates deoxycytidines in single-stranded DNA.AID initiates both somatic hypermutation (SHM) and classswitch recombination (CSR) during antibody diversification (7,8). A number of cofactors have been identified by a combination of genetic and proteomic approaches, which suggest that AID synchronizes with other broadly important cellular pathways including, but not limited to, RNA splicing and processing (9, 10), cellular trafficking (11)(12)(13)(14), and transcription/RNA polymerase stalling (8,(15)(16)(17); however, a concise picture of the players involved in the AID reaction and the...

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The splicing regulator PTBP2 interacts with the cytidine deaminase AID and promotes binding of AID to switch-region DNA

Cited by 110 publications

References 36 publications

Regulation of AID, the B-cell genome mutator

Regulation of AID, the B-cell genome mutator

Efficient AID targeting of switch regions is not sufficient for optimal class switch recombination

Solubility-based genetic screen identifies RING finger protein 126 as an E3 ligase for activation-induced cytidine deaminase

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