Regulation of V(D)J Recombination Activator Protein RAG-2 by Phosphorylation

Lin, Weei Chin; Desiderio, Stephen

doi:10.1126/science.8493533

Cited by 192 publications

(124 citation statements)

References 44 publications

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“…As the non-core region of RAG2 is highly conserved throughout evolution, it was proposed that it regulates in vivo recombinase activity at one or more of the control layers mentioned above. One known function of this part of RAG2 is indeed to restrict DNA cleavage to the G0/G1 phase of the cell cycle and this is mediated by phosphorylation of T490 [ 16,17 ].…”

Section: Introductionmentioning

confidence: 99%

The PHD domain of the sea urchin RAG2 homolog, SpRAG2L, recognizes dimethylated lysine 4 in histone H3 tails

Wilson

Norton

Fugmann

2008

Developmental & Comparative Immunology

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V(D)J recombination is a somatic gene rearrangement process that assembles antigen receptor genes from individual segments during lymphocyte development. The access of the RAG1/RAG2 recombinase to these gene segments is regulated at the level of chromatin modifications, in particular histone tail modifications. Trimethylation of lysine 4 in histone H3 (H3K4me3) correlates with actively recombining gene elements, and this mark is recognized and interpreted by the plant homeodomain (PHD) of RAG2. Here we report that the PHD domain of the only known invertebrate homolog of RAG2, the SpRAG2L protein of the purple sea urchin (Strongylocentrotus purpuratus) also binds to methylated histones, but with a unique preference for H3K4me2. While the cognate substrate for the sea urchin RAG1L/RAG2L complex remains elusive, the affinity for histone tails and the nuclear localization of ectopically expressed SpRAG2L strongly support the model that this enzyme complex exerts its activity on DNA in the context of chromatin.

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Section: Introductionmentioning

confidence: 99%

The PHD domain of the sea urchin RAG2 homolog, SpRAG2L, recognizes dimethylated lysine 4 in histone H3 tails

Wilson

Norton

Fugmann

2008

Developmental & Comparative Immunology

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“…Recent data from Lin and Desiderio show that RAG-2 protein levels in transfected fibroblasts are regulated via a phosphorylation-dependent degradation pathway (Lin and Desiderio 1993). Furthermore, studies on the coordination of DNA repair with the cell cycle have revealed that cells sustaining DNA damage arrest their progression through the cell cycle until the damage has been repaired.…”

Section: Cell Cycle Regulation Of the V(d)j Recombinase Activitymentioning

confidence: 99%

Double-strand signal sequence breaks in V(D)J recombination are blunt, 5'-phosphorylated, RAG-dependent, and cell cycle regulated.

Schlissel

Constantinescu²,

Morrow³

et al. 1993

Genes & Development

360

344

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Immunoglobulin and T-cell receptor genes are assembled during lymphocyte development by a novel, highly regulated series of gene rearrangement reactions known as V(D)I recombination. All rearranging loci are flanked by conserved heptamer-nonamer recombination signal sequences. Gene rearrangement results in the imprecise fusion of coding sequences and the precise fusion of signal sequences. DNA molecules with double-stranded breaks near signal sequences have been detected in cells undergoing V(D)I recombination of the TCR8 locus. We have devised a ligation-mediated PCR assay that detects broken-ended molecules in purified genomic DNA. Using this assay we found that DNA breaks occurring precisely at the signal sequence-coding sequence junction are a general feature of V(D)I recombination, appearing in association with each type of rearranging immunoglobulin gene segment. We show that a significant fraction of these broken ends are blunt and 5'-phosphorylated. In addition, detection of these broken-ended signal sequences is dependent on the activity of RAG-1 and RAG-2, and is restricted to the Go/G1 phase of the cell cycle

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“…5B). Furthermore, RAG2 protein, which can be regulated either at the mRNA level [25] or via phosphorylation and subsequent degradation in cycling cells [26,27], was not downregulated in DN (Fig. 5C) and DN3 (data not shown) thymocytes from all three strains of TCRb Tg mice.…”

Section: Pta-dependent Allelic and Isotypic Exclusion Occur Despite Nmentioning

confidence: 84%

“…The same result was obtained when sorted DN3 thymocytes were analyzed. [26] of the RAG proteins. With regard to the latter point, our failure to observe down-regulation of RAG1 mRNA or RAG2 protein expression in DN3 thymocytes in the presence of a TCRb transgene does not support a direct role for pre-TCR signaling in the regulation of RAG expression.…”

Section: Discussionmentioning

confidence: 99%

“…In this context, our data with TCRb Tg mice as well as other results with DN3 thymocytes from normal mice [1] clearly implicate pTa as being required for allelic exclusion. Possible consequences of pre-TCR signaling that might regulate allelic exclusion include modifications in chromatin accessibility [30] or contraction [31] at the TCRb locus itself as well as changes in the expression [32] or stability [26] of the RAG proteins. With regard to the latter point, our failure to observe down-regulation of RAG1 mRNA or RAG2 protein expression in DN3 thymocytes in the presence of a TCRb transgene does not support a direct role for pre-TCR signaling in the regulation of RAG expression.…”

Section: Discussionmentioning

confidence: 99%

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A critical lineage‐nonspecific role for pTα in mediating allelic and isotypic exclusion in TCRβ‐transgenic mice

Ferrero¹,

Grosjean²,

Fiorini³

et al. 2007

Eur J Immunol

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Although it is well established that early expression of TCRb transgenes in the thymus leads to efficient inhibition of both endogenous TCRb and TCRc rearrangement (also known as allelic and "isotypic" exclusion, respectively) the role of pTa in these processes remains controversial. Here, we have systematically re-evaluated this issue using three independent strains of TCRb-transgenic mice that differ widely in transgene expression levels, and a sensitive intracellular staining assay that detects endogenous TCRVb expression in individual immature thymocytes. In the absence of pTa, both allelic and isotypic exclusion were reversed in all three TCRb-transgenic strains, clearly demonstrating a general requirement for pre-TCR signaling in the inhibition of endogenous TCRb and TCRc rearrangement. Both allelic and isotypic exclusion were pTa dose dependent when transgenic TCRb levels were subphysiological. Moreover, pTa-dependent allelic and isotypic exclusion occurred in both ab and cd T cell lineages, indicating that pre-TCR signaling can potentially be functional in cd precursors. Finally, levels of endogenous RAG1 and RAG2 were not down-regulated in TCRb-transgenic immature thymocytes undergoing allelic or isotypic exclusion. Collectively, our data reveal a critical but lineage-nonspecific role for pTa in mediating both allelic and isotypic exclusion in TCRb-transgenic mice. IntroductionT cells can be divided into ab and cd lineages based on their expression of TCRab or TCRcd. During development in the thymus, ab and cd lineages separate at an early CD4 -CD8 -double-negative (DN) stage, but the precise mechanism of lineage divergence remains controversial.One molecule that has been postulated to play a key role in ab/cd lineage commitment is the pTa chain. pTa is a critical component of the pre-TCR which consists, in addition, of a functionally rearranged TCRb chain and CD3 signaling components. Signaling through the pre-TCR has been reported to be responsible for many important functions during the development of ab lineage cells, including TCRb allelic exclusion [1-3], TCRc silencing [4], and extensive proliferation during the transition from DN to CD4 + CD8 + double-positive (DP) stages [5]. Since pTa -/-mice have an increased number of cd cells that harbor an increased frequency of in-frame TCRb rearrangements [6], it has also been proposed that the pre-TCR favors ab lineage commitment at the expense of cd cells [6]. Since functions of pTa are often difficult to study in normal mice, several groups have crossed pTa-deficient mice with TCRb-transgenic (Tg) mice to assess various putative roles for the pre-TCR during thymus development [7,8]. However, the results of these studies are in many cases controversial and it is still not known whether transgenic "artifacts" caused by overexpression or premature expression of the transgenic TCRb chain may obscure the contribution of pTa to the observed phenotypes.In order to re-evaluate this issue in a systematic manner, we have utilized three independent TCRb Tg mouse...

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Regulation of V(D)J Recombination Activator Protein RAG-2 by Phosphorylation

Cited by 192 publications

References 44 publications

The PHD domain of the sea urchin RAG2 homolog, SpRAG2L, recognizes dimethylated lysine 4 in histone H3 tails

The PHD domain of the sea urchin RAG2 homolog, SpRAG2L, recognizes dimethylated lysine 4 in histone H3 tails

Double-strand signal sequence breaks in V(D)J recombination are blunt, 5'-phosphorylated, RAG-dependent, and cell cycle regulated.

A critical lineage‐nonspecific role for pTα in mediating allelic and isotypic exclusion in TCRβ‐transgenic mice

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