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B lineage-specific regulation of V(D)J recombinase activity is established in common lymphoid progenitors.

Borghesi L, Hsu LY, Miller JP, Anderson M, Herzenberg L, Herzenberg L, Schlissel MS, Allman D, Gerstein RM - J. Exp. Med. (2004)

Bottom Line: Evidence of this recombinase activity is detectable in all four progeny lineages (B, T, and NK, and DC), and rag2 levels are the highest in progenitor subsets immediately downstream of the CLP.By single cell PCR, we demonstrate that V(D)J rearrangements are detectable at IgH loci in approximately 5% of splenic natural killer cells.As activity of the Erag enhancer is restricted to the B cell lineage, this provides the first molecular evidence for establishment of a lineage-specific transcription program in multipotent progenitors.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester 01655, USA.

ABSTRACT
Expression of V(D)J recombinase activity in developing lymphocytes is absolutely required for initiation of V(D)J recombination at antigen receptor loci. However, little is known about when during hematopoietic development the V(D)J recombinase is first active, nor is it known what elements activate the recombinase in multipotent hematopoietic progenitors. Using mice that express a fluorescent transgenic V(D)J recombination reporter, we show that the V(D)J recombinase is active as early as common lymphoid progenitors (CLPs) but not in the upstream progenitors that retain myeloid lineage potential. Evidence of this recombinase activity is detectable in all four progeny lineages (B, T, and NK, and DC), and rag2 levels are the highest in progenitor subsets immediately downstream of the CLP. By single cell PCR, we demonstrate that V(D)J rearrangements are detectable at IgH loci in approximately 5% of splenic natural killer cells. Finally, we show that recombinase activity in CLPs is largely controlled by the Erag enhancer. As activity of the Erag enhancer is restricted to the B cell lineage, this provides the first molecular evidence for establishment of a lineage-specific transcription program in multipotent progenitors.

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Related in: MedlinePlus

V(D)J recombinase activity in multipotent hematopoietic progenitors. (A) V(D)J recombinase activity in CLPs. The lin− subset (B220, CD11b, GR-1, Ter119, CD3) of bone marrow obtained from SB88 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression in IL-7Rα+AA4.1+Sca-1lo/− cells. (B) The lin− subset of bone marrow obtained from SB110 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression as a function of c-kit and CD27. The data are representative of two to five independent experiments.
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fig3: V(D)J recombinase activity in multipotent hematopoietic progenitors. (A) V(D)J recombinase activity in CLPs. The lin− subset (B220, CD11b, GR-1, Ter119, CD3) of bone marrow obtained from SB88 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression in IL-7Rα+AA4.1+Sca-1lo/− cells. (B) The lin− subset of bone marrow obtained from SB110 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression as a function of c-kit and CD27. The data are representative of two to five independent experiments.

Mentions: We have demonstrated that V(D)J recombinase activity is detectable in the earliest B and T lineage progenitors before IgH (and TCR) recombination (23). One of the major implications of this result is that the recombinase may be expressed even before B lineage commitment. To explore this possibility, we examined VEX expression within the lin−IL-7Rα+AA4.1+Sca-1lo subset of bone marrow, which contains hematopoietic precursors that retain lymphoid (B, T, NK, and DC), but not myeloid developmental potential (27, 28), and are designated as common lymphoid progenitors or CLPs. VEX expression is readily detectable in 30–45% of CLPs (Fig. 3 A and not depicted; see also Fig. 6).


B lineage-specific regulation of V(D)J recombinase activity is established in common lymphoid progenitors.

Borghesi L, Hsu LY, Miller JP, Anderson M, Herzenberg L, Herzenberg L, Schlissel MS, Allman D, Gerstein RM - J. Exp. Med. (2004)

V(D)J recombinase activity in multipotent hematopoietic progenitors. (A) V(D)J recombinase activity in CLPs. The lin− subset (B220, CD11b, GR-1, Ter119, CD3) of bone marrow obtained from SB88 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression in IL-7Rα+AA4.1+Sca-1lo/− cells. (B) The lin− subset of bone marrow obtained from SB110 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression as a function of c-kit and CD27. The data are representative of two to five independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211824&req=5

fig3: V(D)J recombinase activity in multipotent hematopoietic progenitors. (A) V(D)J recombinase activity in CLPs. The lin− subset (B220, CD11b, GR-1, Ter119, CD3) of bone marrow obtained from SB88 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression in IL-7Rα+AA4.1+Sca-1lo/− cells. (B) The lin− subset of bone marrow obtained from SB110 H2-SVEX transgenic or C57BL/6 control mice was examined for VEX expression as a function of c-kit and CD27. The data are representative of two to five independent experiments.
Mentions: We have demonstrated that V(D)J recombinase activity is detectable in the earliest B and T lineage progenitors before IgH (and TCR) recombination (23). One of the major implications of this result is that the recombinase may be expressed even before B lineage commitment. To explore this possibility, we examined VEX expression within the lin−IL-7Rα+AA4.1+Sca-1lo subset of bone marrow, which contains hematopoietic precursors that retain lymphoid (B, T, NK, and DC), but not myeloid developmental potential (27, 28), and are designated as common lymphoid progenitors or CLPs. VEX expression is readily detectable in 30–45% of CLPs (Fig. 3 A and not depicted; see also Fig. 6).

Bottom Line: Evidence of this recombinase activity is detectable in all four progeny lineages (B, T, and NK, and DC), and rag2 levels are the highest in progenitor subsets immediately downstream of the CLP.By single cell PCR, we demonstrate that V(D)J rearrangements are detectable at IgH loci in approximately 5% of splenic natural killer cells.As activity of the Erag enhancer is restricted to the B cell lineage, this provides the first molecular evidence for establishment of a lineage-specific transcription program in multipotent progenitors.

View Article: PubMed Central - PubMed

Affiliation: Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester 01655, USA.

ABSTRACT
Expression of V(D)J recombinase activity in developing lymphocytes is absolutely required for initiation of V(D)J recombination at antigen receptor loci. However, little is known about when during hematopoietic development the V(D)J recombinase is first active, nor is it known what elements activate the recombinase in multipotent hematopoietic progenitors. Using mice that express a fluorescent transgenic V(D)J recombination reporter, we show that the V(D)J recombinase is active as early as common lymphoid progenitors (CLPs) but not in the upstream progenitors that retain myeloid lineage potential. Evidence of this recombinase activity is detectable in all four progeny lineages (B, T, and NK, and DC), and rag2 levels are the highest in progenitor subsets immediately downstream of the CLP. By single cell PCR, we demonstrate that V(D)J rearrangements are detectable at IgH loci in approximately 5% of splenic natural killer cells. Finally, we show that recombinase activity in CLPs is largely controlled by the Erag enhancer. As activity of the Erag enhancer is restricted to the B cell lineage, this provides the first molecular evidence for establishment of a lineage-specific transcription program in multipotent progenitors.

Show MeSH
Related in: MedlinePlus