Developmental Regulation of TCRδ Locus Accessibility and Expression by the TCRδ Enhancer

Monroe, R. J.; Sleckman, Barry P.; Monroe, Brianna; Khor, Bernard; Claypool, Steven M.; Ferrini, Roger; Davidson, Laurie A.; Alt, Frederick W.

doi:10.1016/s1074-7613(00)80050-3

Cited by 59 publications

(79 citation statements)

References 56 publications

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“…This may result from the inactivity of E␣ in DN thymocytes (11,14). However, E␦ is active in DN thymocytes and promotes the accessibility of TCR␦ gene segments, including V␦5 (see Results), that lie immediately Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110 upstream of the TEA promoter (2,15). How is it that E␦ is capable of activating the V␦5 promoter, which lies 10 kb downstream, but not the TEA promoter, which lies 14 kb downstream (Fig.…”

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confidence: 96%

Developmental Stage-Specific Regulation of TCR-α-Chain Gene Assembly by Intrinsic Features of the TEA Promoter

Huang

Sleckman

2007

The Journal of Immunology

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The TCR δ- and α-chain genes lie in a single complex locus, the TCRα/δ locus. TCRδ-chain genes are assembled in CD4−CD8− (double negative (DN)) thymocytes and TCRα-chain genes are assembled in CD4+CD8+ (double positive) thymocytes due, in part, to the developmental stage-specific activities of the TCRδ and TCRα enhancers (Eδ and Eα), respectively. Eδ functions with TCRδ promoters to mediate TCRδ-chain gene assembly in DN thymocytes. However, Eδ is unable to function with TCRα promoters such as the TEA promoter to drive TCRα-chain gene assembly in these cells. This is important, because the premature assembly of TCRα-chain genes in DN thymocytes would disrupt αβ and γδ T cell development. The basis for TEA inactivity in DN thymocytes is unclear, because Eδ can activate the Vδ5 gene segment promoter that lies only 4 kb upstream of TEA promoter. In this study, we use gene targeting to construct a modified TCRα/δ locus (TCRα/δ5ΔT) in which the TEA promoter lies in the same location as the Vδ5 gene segment on the wild-type TCRα/δ allele. Remarkably, the TEA promoter on this allele exhibits normal developmental stage-specific regulation, being active in double positive thymocytes but not in DN thymocytes as is the case with the Vδ5 promoter. Thus, the inactivity of the TEA promoter in DN thymocytes is due primarily to intrinsic developmental stage-specific features of the promoter itself and not to its location relative to other cis-acting elements in the locus, such as Eδ.

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confidence: 96%

Developmental Stage-Specific Regulation of TCR-α-Chain Gene Assembly by Intrinsic Features of the TEA Promoter

Huang

Sleckman

2007

The Journal of Immunology

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“…Cre-deleted clones were identified via Southern blot analysis with the 5Ј probe on EcoRV-digested DNA. The F 1 E␦⌬E␣⌬ and F 1 E␦⌬ ES cells have been described (17). F 1 ES clones with Cre-mediated deletion of TCR␣͞␦ locus sequences between the loxP sites inserted in place of the endogenous E␦ element and just 5Ј of E␦R and E␣⌬ were identified via Southern blot analysis with the 5ЈE␦ knockout (KO) probe on XbaI-digested DNA.…”

Section: Methodsmentioning

confidence: 99%

“…The isolation of purified ␥␦ and ␣␤ T cells and the generation of ␥␦ and ␣␤ T cell hybridomas were conducted as described (19). TCR␣ and -␦ gene rearrangements were analyzed as described (17,19,28).…”

Section: Was Used To Generate E␦r͞e␦r Es Cells Generation Of Es Cellmentioning

confidence: 99%

“…Germ-line promoters are associated with each V␣͞V␦ segment (7), the T early ␣ (TEA) promoter and a second J␣ germ-line promoter reside upstream of the most 5Ј J␣s (14,15), and a transcriptional promoter may reside between D␦2 and J␦1 (16). E␦ functions with additional element(s) to mediate TCR␦ germ-line transcription and TCR␦ accessibility in DN pro-T cells (17,18), but only partially contributes to the transcription of assembled VDJ␦ genes in mature ␥␦ T cells (17). E␣ is required for J␣ germ-line transcription and TCR␣ rearrangements involving all J␣ segments in DP thymocytes, as well as transcription of assembled VJ␣ genes in mature ␣␤ T cells and assembled VDJ␦ genes in mature ␥␦ T cells (19).…”

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confidence: 99%

“…In the endogenous TCR␣͞␦ locus, E␣ clearly mediates recombinational accessibility at a distance of at least 70 kb to the most 5Ј J␣s as well as transcription at distances of Ϸ100 kb to the promoters of assembled VDJ␦ segments (19). E␦ is known to stimulate local recombinational accessibility in a transgenic TCR␦ minilocus (21) and, in the murine TCR␣͞␦ locus, can at least mediate transcription and accessibility at a distance of 18 kb to D␦1 (17). However, despite a similar distance between E␦ and the J␣ cluster, E␦ does not direct V␦ or V␣-to-J␣ rearrangement.…”

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confidence: 99%

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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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Vα gene replacement in a TCRα knock-in mouse

et al. 2001

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Using a TCRα chain knock‐in mouse, we demonstrate that V‐gene replacement can operate in the T cell receptor α locus. Functional TCRα chain transcripts generated by Vα‐gene replacement at the site of the Vα‐embedded heptamer were identified in splenic T cells. This finding shows that Vα‐gene replacement can likely be used to shape the peripheral T cell repertoire.The conservation of the embedded heptamer in most Vα segments adds support to the notion that V‐gene replacement is a mechanism maintained to diversify the immune system and that argues that itis common to B and T cells.

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Developmental Regulation of TCRδ Locus Accessibility and Expression by the TCRδ Enhancer

Cited by 59 publications

References 56 publications

Developmental Stage-Specific Regulation of TCR-α-Chain Gene Assembly by Intrinsic Features of the TEA Promoter

Developmental Stage-Specific Regulation of TCR-α-Chain Gene Assembly by Intrinsic Features of the TEA Promoter

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

Vα gene replacement in a TCRα knock-in mouse

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