Limited effect of chromatin remodeling on Dβ-to-Jβ recombination in CD4+CD8+ thymocyte: implications for a new aspect in the regulation of TCR β gene recombination

Senoo, Makoto; Mochida, Nahoko; Wang, Lili; Matsumura, Yukiko; Suzuki, Daisuke; Takeda, Nobuo; Shinkai, Yoichi; Habu, Sonoko

doi:10.1093/intimm/13.11.1405

Cited by 17 publications

(15 citation statements)

References 41 publications

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“…However, positioned at their own chromosomal location, such reduced hubs mostly failed in sustaining recombination efficiently (41) (this study). More generally, even when promoting recombination within synthetic transgenes, TCR/Ig enhancers often do not work properly at heterologous sites (13,(41)(42)(43)(44). The discordant results are unlikely due to a loss of enhancer function at knockin alleles caused by gene targeting.…”

Section: Discussionmentioning

confidence: 99%

Duality of Enhancer Functioning Mode Revealed in a Reduced TCRβ Gene Enhancer Knockin Mouse Model

Bonnet

Huang

Benoukraf

et al. 2009

The Journal of Immunology

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The TCRβ gene enhancer (Eβ) commands TCRβ gene expression through the lifespan of T lymphocytes. Genetic and molecular studies have implied that in early thymocytes, Eβ directs chromatin opening over the Dβ-Jβ-Cβ domains and triggers initial Dβ-Jβ recombination. In mature T cells, Eβ is required for expression of the assembled TCRβ gene. Whether these separate activities rely on distinct Eβ regulatory sequences and involve differing modes of activation is unclear. Using gene targeting in mouse embryonic stem cells, we replaced Eβ by a conserved core fragment (Eβ169). We found that Eβ169-carrying alleles were capable of sustaining β gene expression and the development of mature T cells in homozygous knockin mice. Surprisingly, these procedures and underlying molecular transactions were affected to a wide range of degrees depending on the developmental stage. Early thymocytes barely achieved Dβ-Jβ germline transcription and recombination. In contrast, T cells displayed substantial though heterogeneous levels of VDJ-rearranged TCRβ gene expression. Our results have implications regarding enhancer function in cells of the adaptive immune system and, potentially, TCRβ gene recombination and allelic exclusion.

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Section: Discussionmentioning

confidence: 99%

Duality of Enhancer Functioning Mode Revealed in a Reduced TCRβ Gene Enhancer Knockin Mouse Model

Bonnet

Huang

Benoukraf

et al. 2009

The Journal of Immunology

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“…Therefore, it is likely that the Eß-independent Jß accessibility could occur in a certain developmental stage where p53 expression is inactivated. Some studies have also shown that Eß-independent Jß accessibility increases during DN to DP thymocyte differentiation (20,31), and the DN to DP transition of thymocytes was suggested to be dependent on p53 inactivation (32). As p53 is known as a chromatin accessibility factor and p53-mediated chromosomal accessibility or inaccessibility is possible (33,34), it is possible that Jß loci become accessible to RAG-mediated cleavage in the absence of p53 during the progression of lymphomagenesis.…”

Section: Discussionmentioning

confidence: 99%

Aberrant V(D)J cleavages in T cell receptor β enhancer- and p53-deficient lymphoma cells

Kang

Son²,

Lee³

et al. 2010

Oncol Rep

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Abstract. Previously, we generated thymic lymphoma cell lines from Eß R/R p53 -/-(EP) double mutant mice where the T cell receptor (TCR) ß enhancer (Eß) was deleted, and the p53 gene was inactivated. Here, we characterized the EP cell lines to study the roles of the Eß and p53 on TCRß rearrangements during lymphomagenesis. Recombination activation genes (RAGs) were expressed, while the TCRß chain was not expressed in the EP cell lines. Dß-Jß rearrangements were not detected at all, and Dß1 and Dß2 cleavages were also not detected in the EP cell lines. However, Jß cleavages suppressed in Eß mutant thymocytes were readily detected in the EP cell lines. The Jß cleavages appeared to be uncoupled, aberrant, RAG-dependent and Eß-independent and were not detected in a p53 or Eß single mutant background, suggesting that the Jß cleavages are selected in the Eß and p53 double mutant background. Sequence analysis showed that the cleavage occurred in the cryptic recombination signal sequences (RSSs) present throughout Jß gene segments. The results implicate that the uncoupled and aberrant V(D)J cleavages may contribute to double-strand break-mediated genome instability during lymphomagenesis in EP mice.

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“…Endogenous iE promotes accessibility at a distance of at least 4 kb to assembled DJ H 1 complexes and, after V H -to-DJ H rearrangement, appears capable of stimulating transcription of an 5Ј germ-line V H promoter at a distance of 17.5 kb (45). Furthermore, iE can also replace E␤ function within the endogenous TCR␤ locus to promote D␤1 accessibility (39,40), a process dependent on activation of the D␤1 germ-line promoter (46,47), at a distance of 21 kb.…”

Section: Discussionmentioning

confidence: 99%

“…In this regard, a 116-bp core fragment of human E␣ that lacks several trans-factor binding sites has been shown to promote the complete assembly of a transgenic TCR␦ minilocus (37). Furthermore, heterologous enhancer elements can promote accessibility in many contexts (38), including within the endogenous TCR␤ locus where E␣ and iE can replace E␤ function (39,40). To further evaluate the extent to which TCR␣͞␦ locus 3Ј enhancer identity may be critical for chromosomal V␣-to-J␣ rearrangement, we investigated whether E␣C or iE could substitute for E␣ function.…”

Section: E␦ Does Not Promote Efficient J␣ Accessibility When Located mentioning

confidence: 99%

T cell receptor (TCR) α/δ locus enhancer identity and position are critical for the assembly of TCR δ and α variable region genes

Bassing

Tillman

Woodman

et al. 2003

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

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T cell receptor (TCR) ␦ and ␣ variable region genes are assembled from germ-line gene segments located in a single chromosomal locus in which TCR␦ segments are situated between TCR␣ segments. The TCR␣ enhancer (E␣) located at the 3 end of the TCR␣͞␦ locus functions over a long chromosomal distance to promote TCR␣ rearrangement and maximal TCR␦ expression; whereas the TCR␦ enhancer (E␦) is located among the TCR␦ segments and functions with additional element(s) to mediate TCR␦ rearrangement. We used gene-targeted mutation to evaluate whether the identity of E␣ and the position of E␦ are critical for the developmental stage-specific assembly of TCR ␦ and ␣ variable region genes. Specific replacement of E␣ with E␦, the core E␣ element (E␣C), or the Ig heavy chain intronic enhancer (iE ), all of which promote accessibility in the context of transgenic V(D)J recombination substrates, did not promote a significant level of TCR␣ rearrangement beyond that observed in the absence of E␣. Therefore, the identity and full complement of E␣-binding sites are critical for promoting accessibility within the TCR␣ locus. In the absence of the endogenous E␦ element, specific replacement of E␣ with E␦ also did not promote TCR␦ rearrangement. However, deletion of intervening TCR␣͞␦ locus sequences to restore the inserted E␦ to its normal chromosomal position relative to 5 sequences rescued TCR␦ rearrangement. Therefore, unlike E␣, E␦ lacks ability to function over the large intervening TCR␣ locus and͞or E␦ function requires proximity to additional upstream element(s) to promote TCR␦ accessibility.T he exons that encode T cell receptor (TCR) and Ig variable regions are assembled during lymphocyte development from component variable (V), diversity (D), and joining (J) gene segments (1, 2). Both ␣␤ and ␥␦ T cells develop from CD4 Ϫ ͞ CD8 Ϫ (double negative, DN) thymocytes in which TCR␤, -␥, and -␦ genes are all assembled (3). Productive VDJ␤ rearrangements generate TCR␤ chains that associate with surrogate TCR␣ chains to form preTCRs that signal expansion and differentiation to the CD4 ϩ ͞CD8 ϩ (double positive, DP) thymocyte stage (4, 5). Functional VJ␣ rearrangements in DP cells generate TCR␣ chains that, when expressed as surface ␣␤ TCR, direct cellular selection and development to the CD4 ϩ or CD8 ϩ (single positive, SP) thymocytes that exit the thymus as mature ␣␤ T cells (6). Alternatively, productive VDJ␦ and VJ␥ rearrangements in DN progenitor (pro-) T cells generate TCR␦ and -␥ chains that form cell surface ␥␦ TCR and direct ␥␦ T cell development (4, 5).The TCR␣͞␦ locus spans 1 Mb and contains variable region gene segments for two distinct antigen receptors (7). The 5Ј end of the locus consists of a cluster of Ϸ90 V␣͞V␦ gene segments with V␦s concentrated near the 3Ј end of the cluster, and the 3Ј end of the locus consists of a cluster of 50 J␣ segments that spans Ϸ60 kb followed by the TCR␣ constant region (C␣). The D␦ (D␦1 and D␦2) and J␦ (J␦1 and J␦2) segments, the TCR␦ constant region (C␦) and V␦5 lie between the V␣͞V␦ and...

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Limited effect of chromatin remodeling on Dβ-to-Jβ recombination in CD4+CD8+ thymocyte: implications for a new aspect in the regulation of TCR β gene recombination

Cited by 17 publications

References 41 publications

Duality of Enhancer Functioning Mode Revealed in a Reduced TCRβ Gene Enhancer Knockin Mouse Model

Duality of Enhancer Functioning Mode Revealed in a Reduced TCRβ Gene Enhancer Knockin Mouse Model

Aberrant V(D)J cleavages in T cell receptor β enhancer- and p53-deficient lymphoma cells

T cell receptor (TCR) α/δ locus enhancer identity and position are critical for the assembly of TCR δ and α variable region genes

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