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The CD3-gammadeltaepsilon and CD3-zeta/eta modules are each essential for allelic exclusion at the T cell receptor beta locus but are both dispensable for the initiation of V to (D)J recombination at the T cell receptor-beta, -gamma, and -delta loci.

Ardouin L, Ismaili J, Malissen B, Malissen M - J. Exp. Med. (1998)

Bottom Line: The pre-T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-beta chain.Furthermore, using mutant mice lacking both the CD3-epsilon and CD3-zeta/eta genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-beta, TCR-gamma, and TCR-delta loci.Thus, the CD3 components are differentially involved in the sequential events that make the TCR-beta locus first accessible to, and later insulated from, the action of the V(D)J recombinase.

View Article: PubMed Central - PubMed

Affiliation: Centre d'Immunologie Institut National de la Santé et de la Recherche Médicale-Centre National de la Recherche Scientifique de Marseille-Luminy, Case 906, 13288 Marseille Cedex 9, France.

ABSTRACT
The pre-T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-beta chain. Recent experiments in pre-Talpha chain-deficient mice have suggested that the pre-TCR may not be required for signaling allelic exclusion at the TCR-beta locus. Using CD3-epsilon- and CD3-zeta/eta-deficient mice harboring a productively rearranged TCR-beta transgene, we showed that the CD3-gammadeltaepsilon and CD3-zeta/eta modules, and by inference the pre-TCR/CD3 complex, are each essential for the establishment of allelic exclusion at the endogenous TCR-beta locus. Furthermore, using mutant mice lacking both the CD3-epsilon and CD3-zeta/eta genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-beta, TCR-gamma, and TCR-delta loci. Thus, the CD3 components are differentially involved in the sequential events that make the TCR-beta locus first accessible to, and later insulated from, the action of the V(D)J recombinase.

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T cell development  in CD3-εΔ5/Δ5CD3-ζ/η−/−  double mutant mice. Mice with  εΔ5/Δ5ζ/η+/+, ε+/+ζ/η−/−, ε+/Δ5  ζ/η−/−, and εΔ5/Δ5ζ/η−/− genotypes were derived from an F2 intercross between CD3-εΔ5/Δ5 and  CD3-ζ/η−/− mutant mice. Total thymocytes were analyzed by  flow cytometry for the expression of CD4 versus CD8 (A) and  CD25 versus CD44 (B). The  percentages of cells found in  each quadrant is indicated.
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Figure 6: T cell development in CD3-εΔ5/Δ5CD3-ζ/η−/− double mutant mice. Mice with εΔ5/Δ5ζ/η+/+, ε+/+ζ/η−/−, ε+/Δ5 ζ/η−/−, and εΔ5/Δ5ζ/η−/− genotypes were derived from an F2 intercross between CD3-εΔ5/Δ5 and CD3-ζ/η−/− mutant mice. Total thymocytes were analyzed by flow cytometry for the expression of CD4 versus CD8 (A) and CD25 versus CD44 (B). The percentages of cells found in each quadrant is indicated.

Mentions: The molecular mechanisms regulating the development of B cells and α/β T cells display striking similarities (see review in references 33 and 34). For instance, pre–B cells express a B cell analogue of the pre–T cell receptor called the pre–B cell receptor. The pre–B cell receptor associates with Igα/Igβ transducing subunits and triggers both the selective amplification/maturation of IgH+ pre–B cells and establishement of allelic exclusion at the IgH locus (34). Igβ-deficient mice show a complete block in B cell development at a stage corresponding to the CD44−/lowCD25+ stage of T cell development (35). Interestingly, VH to DHJH rearrangements were found to be severely reduced in Igβ-deficient mice, whereas DH to JH rearrangements proceeded normally. This indicated that Ig-β may play an important regulatory role in the onset of VH to DHJH recombination. When bred separately, the CD3-εΔ5 and CD3-ζ/η mutations had no discernible effect on the occurrence and extent of Vβ to DβJβ recombination (Figs. 4 and 5). Therefore, the V to DJ recombination events affecting TCR-β and IgH loci may be subjected to distinct regulatory signals. It is also possible, however, that the CD3-ε and CD3-ζ/η chains play redundant regulatory roles in the onset of Vβ to DβJβ recombination. To address this question, mice lacking both proteins were derived from a F2 intercross between CD3-εΔ5/Δ5 and CD3-ζ/η−/− mice. As shown in Fig. 6, mice lacking both CD3-ε and CD3-ζ/η chains had thymuses the size and surface phenotype of which closely resemble those found in parental CD3-εΔ5/Δ5 mice (Fig. 7, compare the CD4/CD8 and CD44/CD25 profiles of panels εΔ5/Δ5/ζ/η+/+ and εΔ5/Δ5/ ζ/η−/−). Interestingly, ε+/+ ζ/η−/− and ε+/Δ5 ζ/η−/− thymuses displayed markedly different CD4/CD8 phenotypes, the latter closely resembling in size and composition those developing in εΔ5/Δ5 ζ/η−/− double-mutant mice (Fig. 6). Thus, in the absence of CD3-ζ/η chains, the CD3-εΔ5 mutation manifests a clear gene-dosage effect, suggesting that in a CD3-ζ/η–less context, it is the CD3-ε subunits that limit the number of pre-TCR subcomplexes available for driving the transition to the DP stage.


The CD3-gammadeltaepsilon and CD3-zeta/eta modules are each essential for allelic exclusion at the T cell receptor beta locus but are both dispensable for the initiation of V to (D)J recombination at the T cell receptor-beta, -gamma, and -delta loci.

Ardouin L, Ismaili J, Malissen B, Malissen M - J. Exp. Med. (1998)

T cell development  in CD3-εΔ5/Δ5CD3-ζ/η−/−  double mutant mice. Mice with  εΔ5/Δ5ζ/η+/+, ε+/+ζ/η−/−, ε+/Δ5  ζ/η−/−, and εΔ5/Δ5ζ/η−/− genotypes were derived from an F2 intercross between CD3-εΔ5/Δ5 and  CD3-ζ/η−/− mutant mice. Total thymocytes were analyzed by  flow cytometry for the expression of CD4 versus CD8 (A) and  CD25 versus CD44 (B). The  percentages of cells found in  each quadrant is indicated.
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Related In: Results  -  Collection

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Figure 6: T cell development in CD3-εΔ5/Δ5CD3-ζ/η−/− double mutant mice. Mice with εΔ5/Δ5ζ/η+/+, ε+/+ζ/η−/−, ε+/Δ5 ζ/η−/−, and εΔ5/Δ5ζ/η−/− genotypes were derived from an F2 intercross between CD3-εΔ5/Δ5 and CD3-ζ/η−/− mutant mice. Total thymocytes were analyzed by flow cytometry for the expression of CD4 versus CD8 (A) and CD25 versus CD44 (B). The percentages of cells found in each quadrant is indicated.
Mentions: The molecular mechanisms regulating the development of B cells and α/β T cells display striking similarities (see review in references 33 and 34). For instance, pre–B cells express a B cell analogue of the pre–T cell receptor called the pre–B cell receptor. The pre–B cell receptor associates with Igα/Igβ transducing subunits and triggers both the selective amplification/maturation of IgH+ pre–B cells and establishement of allelic exclusion at the IgH locus (34). Igβ-deficient mice show a complete block in B cell development at a stage corresponding to the CD44−/lowCD25+ stage of T cell development (35). Interestingly, VH to DHJH rearrangements were found to be severely reduced in Igβ-deficient mice, whereas DH to JH rearrangements proceeded normally. This indicated that Ig-β may play an important regulatory role in the onset of VH to DHJH recombination. When bred separately, the CD3-εΔ5 and CD3-ζ/η mutations had no discernible effect on the occurrence and extent of Vβ to DβJβ recombination (Figs. 4 and 5). Therefore, the V to DJ recombination events affecting TCR-β and IgH loci may be subjected to distinct regulatory signals. It is also possible, however, that the CD3-ε and CD3-ζ/η chains play redundant regulatory roles in the onset of Vβ to DβJβ recombination. To address this question, mice lacking both proteins were derived from a F2 intercross between CD3-εΔ5/Δ5 and CD3-ζ/η−/− mice. As shown in Fig. 6, mice lacking both CD3-ε and CD3-ζ/η chains had thymuses the size and surface phenotype of which closely resemble those found in parental CD3-εΔ5/Δ5 mice (Fig. 7, compare the CD4/CD8 and CD44/CD25 profiles of panels εΔ5/Δ5/ζ/η+/+ and εΔ5/Δ5/ ζ/η−/−). Interestingly, ε+/+ ζ/η−/− and ε+/Δ5 ζ/η−/− thymuses displayed markedly different CD4/CD8 phenotypes, the latter closely resembling in size and composition those developing in εΔ5/Δ5 ζ/η−/− double-mutant mice (Fig. 6). Thus, in the absence of CD3-ζ/η chains, the CD3-εΔ5 mutation manifests a clear gene-dosage effect, suggesting that in a CD3-ζ/η–less context, it is the CD3-ε subunits that limit the number of pre-TCR subcomplexes available for driving the transition to the DP stage.

Bottom Line: The pre-T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-beta chain.Furthermore, using mutant mice lacking both the CD3-epsilon and CD3-zeta/eta genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-beta, TCR-gamma, and TCR-delta loci.Thus, the CD3 components are differentially involved in the sequential events that make the TCR-beta locus first accessible to, and later insulated from, the action of the V(D)J recombinase.

View Article: PubMed Central - PubMed

Affiliation: Centre d'Immunologie Institut National de la Santé et de la Recherche Médicale-Centre National de la Recherche Scientifique de Marseille-Luminy, Case 906, 13288 Marseille Cedex 9, France.

ABSTRACT
The pre-T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-beta chain. Recent experiments in pre-Talpha chain-deficient mice have suggested that the pre-TCR may not be required for signaling allelic exclusion at the TCR-beta locus. Using CD3-epsilon- and CD3-zeta/eta-deficient mice harboring a productively rearranged TCR-beta transgene, we showed that the CD3-gammadeltaepsilon and CD3-zeta/eta modules, and by inference the pre-TCR/CD3 complex, are each essential for the establishment of allelic exclusion at the endogenous TCR-beta locus. Furthermore, using mutant mice lacking both the CD3-epsilon and CD3-zeta/eta genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-beta, TCR-gamma, and TCR-delta loci. Thus, the CD3 components are differentially involved in the sequential events that make the TCR-beta locus first accessible to, and later insulated from, the action of the V(D)J recombinase.

Show MeSH