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Beta-catenin is dispensable for hematopoiesis and lymphopoiesis.

Cobas M, Wilson A, Ernst B, Mancini SJ, MacDonald HR, Kemler R, Radtke F - J. Exp. Med. (2004)

Bottom Line: Beta-catenin-mediated Wnt signaling has been suggested to be critically involved in hematopoietic stem cell maintenance and development of T and B cells in the immune system.Unexpectedly, here we report that inducible Cre-loxP-mediated inactivation of the beta-catenin gene in bone marrow progenitors does not impair their ability to self-renew and reconstitute all hematopoietic lineages (myeloid, erythroid, and lymphoid), even in competitive mixed chimeras.In contrast to earlier reports, these data exclude an essential role for beta-catenin during hematopoiesis and lymphopoiesis.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, Epalinges, Switzerland.

ABSTRACT
Beta-catenin-mediated Wnt signaling has been suggested to be critically involved in hematopoietic stem cell maintenance and development of T and B cells in the immune system. Unexpectedly, here we report that inducible Cre-loxP-mediated inactivation of the beta-catenin gene in bone marrow progenitors does not impair their ability to self-renew and reconstitute all hematopoietic lineages (myeloid, erythroid, and lymphoid), even in competitive mixed chimeras. In addition, both thymocyte survival and antigen-induced proliferation of peripheral T cells is beta-catenin independent. In contrast to earlier reports, these data exclude an essential role for beta-catenin during hematopoiesis and lymphopoiesis.

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Normal development of β-catenin–deficient B and T cells in mixed BM chimeras. Representative FACS® analyses (left and middle panels) gated on CD45.2+ donor cells. Bar diagrams (right panels) indicate relative number ± SD of the different subsets where n = 12 for both β-cateninlox/lox (open bars) and β-catenin−/− (shaded bars) mice. (a) BM stained with anti-B220 and anti-IgM antibodies. (b) BM cells stained with anti-CD43 and anti-IgM antibodies after gating on B220+ cells. (c) Total thymocytes stained with anti-CD4 and anti-CD8 antibodies. DN (CD4− CD8−), DP (CD4+ CD8+), CD4 (CD4+ CD8− TCRβ+), and CD8 (CD4− CD8+ TCRβ+). (d) Thymocytes stained with anti-CD44 and anti-CD25 antibodies after gating on donor (CD45.2+)-derived lineage-negative cells. DN1 (CD44+ CD25−), DN2 (CD44+ CD25+), DN3 (CD44− CD25+), and DN4 (CD44− CD25−). (e) CD45.2+ (donor) and CD45.1+ (WT) cells derived from chimeric spleens were purified by FACS® sorting to verify deletion of the floxed β-catenin alleles after reconstitution. FACS® analysis before (left) and after the sort (right). Relative purity of the sorted populations are indicated. (f) Southern blot analysis of Eco-RI–digested genomic DNA from sorted CD45.1+ and CD45.2+ donor splenocytes. CD45.1+ cells were pooled from three different mice and CD45.2+ cells are derived from two individual mice.
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fig4: Normal development of β-catenin–deficient B and T cells in mixed BM chimeras. Representative FACS® analyses (left and middle panels) gated on CD45.2+ donor cells. Bar diagrams (right panels) indicate relative number ± SD of the different subsets where n = 12 for both β-cateninlox/lox (open bars) and β-catenin−/− (shaded bars) mice. (a) BM stained with anti-B220 and anti-IgM antibodies. (b) BM cells stained with anti-CD43 and anti-IgM antibodies after gating on B220+ cells. (c) Total thymocytes stained with anti-CD4 and anti-CD8 antibodies. DN (CD4− CD8−), DP (CD4+ CD8+), CD4 (CD4+ CD8− TCRβ+), and CD8 (CD4− CD8+ TCRβ+). (d) Thymocytes stained with anti-CD44 and anti-CD25 antibodies after gating on donor (CD45.2+)-derived lineage-negative cells. DN1 (CD44+ CD25−), DN2 (CD44+ CD25+), DN3 (CD44− CD25+), and DN4 (CD44− CD25−). (e) CD45.2+ (donor) and CD45.1+ (WT) cells derived from chimeric spleens were purified by FACS® sorting to verify deletion of the floxed β-catenin alleles after reconstitution. FACS® analysis before (left) and after the sort (right). Relative purity of the sorted populations are indicated. (f) Southern blot analysis of Eco-RI–digested genomic DNA from sorted CD45.1+ and CD45.2+ donor splenocytes. CD45.1+ cells were pooled from three different mice and CD45.2+ cells are derived from two individual mice.

Mentions: As defects in both B and (more severely) T cell development have been reported in LEF1 and TCF1 gene-targeted mice, respectively, these two lymphoid lineages were analyzed in more detail in mixed BM chimeras. Flow cytometric analysis of B cell subsets in the BM shows that the relative numbers of B220+ IgM+ and B220+ IgM− cells within the CD45.2+ donor population is similar between control and β-catenin–deficient chimeras (Fig. 4 a). Furthermore, the generation of the more immature B220+ CD43+ cells defined as the pro–B cell compartment (Hardy fraction A–C′) in mixed BM chimeras seems not to be perturbed by the absence of β-catenin (Fig. 4 b).


Beta-catenin is dispensable for hematopoiesis and lymphopoiesis.

Cobas M, Wilson A, Ernst B, Mancini SJ, MacDonald HR, Kemler R, Radtke F - J. Exp. Med. (2004)

Normal development of β-catenin–deficient B and T cells in mixed BM chimeras. Representative FACS® analyses (left and middle panels) gated on CD45.2+ donor cells. Bar diagrams (right panels) indicate relative number ± SD of the different subsets where n = 12 for both β-cateninlox/lox (open bars) and β-catenin−/− (shaded bars) mice. (a) BM stained with anti-B220 and anti-IgM antibodies. (b) BM cells stained with anti-CD43 and anti-IgM antibodies after gating on B220+ cells. (c) Total thymocytes stained with anti-CD4 and anti-CD8 antibodies. DN (CD4− CD8−), DP (CD4+ CD8+), CD4 (CD4+ CD8− TCRβ+), and CD8 (CD4− CD8+ TCRβ+). (d) Thymocytes stained with anti-CD44 and anti-CD25 antibodies after gating on donor (CD45.2+)-derived lineage-negative cells. DN1 (CD44+ CD25−), DN2 (CD44+ CD25+), DN3 (CD44− CD25+), and DN4 (CD44− CD25−). (e) CD45.2+ (donor) and CD45.1+ (WT) cells derived from chimeric spleens were purified by FACS® sorting to verify deletion of the floxed β-catenin alleles after reconstitution. FACS® analysis before (left) and after the sort (right). Relative purity of the sorted populations are indicated. (f) Southern blot analysis of Eco-RI–digested genomic DNA from sorted CD45.1+ and CD45.2+ donor splenocytes. CD45.1+ cells were pooled from three different mice and CD45.2+ cells are derived from two individual mice.
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fig4: Normal development of β-catenin–deficient B and T cells in mixed BM chimeras. Representative FACS® analyses (left and middle panels) gated on CD45.2+ donor cells. Bar diagrams (right panels) indicate relative number ± SD of the different subsets where n = 12 for both β-cateninlox/lox (open bars) and β-catenin−/− (shaded bars) mice. (a) BM stained with anti-B220 and anti-IgM antibodies. (b) BM cells stained with anti-CD43 and anti-IgM antibodies after gating on B220+ cells. (c) Total thymocytes stained with anti-CD4 and anti-CD8 antibodies. DN (CD4− CD8−), DP (CD4+ CD8+), CD4 (CD4+ CD8− TCRβ+), and CD8 (CD4− CD8+ TCRβ+). (d) Thymocytes stained with anti-CD44 and anti-CD25 antibodies after gating on donor (CD45.2+)-derived lineage-negative cells. DN1 (CD44+ CD25−), DN2 (CD44+ CD25+), DN3 (CD44− CD25+), and DN4 (CD44− CD25−). (e) CD45.2+ (donor) and CD45.1+ (WT) cells derived from chimeric spleens were purified by FACS® sorting to verify deletion of the floxed β-catenin alleles after reconstitution. FACS® analysis before (left) and after the sort (right). Relative purity of the sorted populations are indicated. (f) Southern blot analysis of Eco-RI–digested genomic DNA from sorted CD45.1+ and CD45.2+ donor splenocytes. CD45.1+ cells were pooled from three different mice and CD45.2+ cells are derived from two individual mice.
Mentions: As defects in both B and (more severely) T cell development have been reported in LEF1 and TCF1 gene-targeted mice, respectively, these two lymphoid lineages were analyzed in more detail in mixed BM chimeras. Flow cytometric analysis of B cell subsets in the BM shows that the relative numbers of B220+ IgM+ and B220+ IgM− cells within the CD45.2+ donor population is similar between control and β-catenin–deficient chimeras (Fig. 4 a). Furthermore, the generation of the more immature B220+ CD43+ cells defined as the pro–B cell compartment (Hardy fraction A–C′) in mixed BM chimeras seems not to be perturbed by the absence of β-catenin (Fig. 4 b).

Bottom Line: Beta-catenin-mediated Wnt signaling has been suggested to be critically involved in hematopoietic stem cell maintenance and development of T and B cells in the immune system.Unexpectedly, here we report that inducible Cre-loxP-mediated inactivation of the beta-catenin gene in bone marrow progenitors does not impair their ability to self-renew and reconstitute all hematopoietic lineages (myeloid, erythroid, and lymphoid), even in competitive mixed chimeras.In contrast to earlier reports, these data exclude an essential role for beta-catenin during hematopoiesis and lymphopoiesis.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, Epalinges, Switzerland.

ABSTRACT
Beta-catenin-mediated Wnt signaling has been suggested to be critically involved in hematopoietic stem cell maintenance and development of T and B cells in the immune system. Unexpectedly, here we report that inducible Cre-loxP-mediated inactivation of the beta-catenin gene in bone marrow progenitors does not impair their ability to self-renew and reconstitute all hematopoietic lineages (myeloid, erythroid, and lymphoid), even in competitive mixed chimeras. In addition, both thymocyte survival and antigen-induced proliferation of peripheral T cells is beta-catenin independent. In contrast to earlier reports, these data exclude an essential role for beta-catenin during hematopoiesis and lymphopoiesis.

Show MeSH
Related in: MedlinePlus