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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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Inducible targeting of the β-catenin gene in the BM by the Mx-Cre recombinase. (a) Schematic representation of the β-catenin protein containing an NH2-terminal region (N-term), 12 Armadillo repeats, and a carboxy terminus harboring the transactivation domain (C-term). The genomic organization of the β-cateninlox/lox locus is shown with cylinders indicating coding exons and small black rectangles indicating noncoding exons. Exons 2–6 are flanked by two loxP sequences (triangles). β-cateninlox/lox mice were crossed to mice carrying the IFN-α–inducible Mx-Cre transgene to inducibly inactivate β-catenin in the BM after pI-pC treatment. Arrows indicate approximate positions of the PCR primers used to verify the deletion of the floxed β-catenin locus. EcoRI restriction sites and the probe for Southern blot analysis are indicated. (b) Southern blot analysis of Eco-RI–digested genomic DNA from BM of WT, β-cateninlox/lox, or β-catenin−/− mice. The probe indicated in (a) reveals a 7-kb fragment for the WT allele, two fragments of 3.8 and 3.2 kb for the homozygously floxed β-catenin locus, and one 5.2-kb fragment for the β-catenin−/− allele after successful deletion of the loxP flanked gene segment. (c) Survival curve of β-cateninlox/lox and β-catenin−/− mice after injection of pI-pC as indicated by arrows. Death of β-catenin−/− mice starts 2 wk after the last injection. n = 8 for both β-cateninlox/lox (controls) and β-catenin−/−.
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fig1: Inducible targeting of the β-catenin gene in the BM by the Mx-Cre recombinase. (a) Schematic representation of the β-catenin protein containing an NH2-terminal region (N-term), 12 Armadillo repeats, and a carboxy terminus harboring the transactivation domain (C-term). The genomic organization of the β-cateninlox/lox locus is shown with cylinders indicating coding exons and small black rectangles indicating noncoding exons. Exons 2–6 are flanked by two loxP sequences (triangles). β-cateninlox/lox mice were crossed to mice carrying the IFN-α–inducible Mx-Cre transgene to inducibly inactivate β-catenin in the BM after pI-pC treatment. Arrows indicate approximate positions of the PCR primers used to verify the deletion of the floxed β-catenin locus. EcoRI restriction sites and the probe for Southern blot analysis are indicated. (b) Southern blot analysis of Eco-RI–digested genomic DNA from BM of WT, β-cateninlox/lox, or β-catenin−/− mice. The probe indicated in (a) reveals a 7-kb fragment for the WT allele, two fragments of 3.8 and 3.2 kb for the homozygously floxed β-catenin locus, and one 5.2-kb fragment for the β-catenin−/− allele after successful deletion of the loxP flanked gene segment. (c) Survival curve of β-cateninlox/lox and β-catenin−/− mice after injection of pI-pC as indicated by arrows. Death of β-catenin−/− mice starts 2 wk after the last injection. n = 8 for both β-cateninlox/lox (controls) and β-catenin−/−.

Mentions: Adult mice received five i.p. injections of 250 μg polyI-polyC (pI-pC; Sigma-Aldrich) at 2-d intervals. 2 d after the last injection, mice were killed and genomic DNA was prepared from BM cells using standard protocols. The deletion efficiency was assessed by Southern blot analysis of EcoRI-digested genomic DNA hybridized with a 7,000-bp EcoRI probe (see Fig. 1; reference 27) and quantified using a PhosphorImager (BAS-1000; Fuji).


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)

Inducible targeting of the β-catenin gene in the BM by the Mx-Cre recombinase. (a) Schematic representation of the β-catenin protein containing an NH2-terminal region (N-term), 12 Armadillo repeats, and a carboxy terminus harboring the transactivation domain (C-term). The genomic organization of the β-cateninlox/lox locus is shown with cylinders indicating coding exons and small black rectangles indicating noncoding exons. Exons 2–6 are flanked by two loxP sequences (triangles). β-cateninlox/lox mice were crossed to mice carrying the IFN-α–inducible Mx-Cre transgene to inducibly inactivate β-catenin in the BM after pI-pC treatment. Arrows indicate approximate positions of the PCR primers used to verify the deletion of the floxed β-catenin locus. EcoRI restriction sites and the probe for Southern blot analysis are indicated. (b) Southern blot analysis of Eco-RI–digested genomic DNA from BM of WT, β-cateninlox/lox, or β-catenin−/− mice. The probe indicated in (a) reveals a 7-kb fragment for the WT allele, two fragments of 3.8 and 3.2 kb for the homozygously floxed β-catenin locus, and one 5.2-kb fragment for the β-catenin−/− allele after successful deletion of the loxP flanked gene segment. (c) Survival curve of β-cateninlox/lox and β-catenin−/− mice after injection of pI-pC as indicated by arrows. Death of β-catenin−/− mice starts 2 wk after the last injection. n = 8 for both β-cateninlox/lox (controls) and β-catenin−/−.
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Related In: Results  -  Collection

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fig1: Inducible targeting of the β-catenin gene in the BM by the Mx-Cre recombinase. (a) Schematic representation of the β-catenin protein containing an NH2-terminal region (N-term), 12 Armadillo repeats, and a carboxy terminus harboring the transactivation domain (C-term). The genomic organization of the β-cateninlox/lox locus is shown with cylinders indicating coding exons and small black rectangles indicating noncoding exons. Exons 2–6 are flanked by two loxP sequences (triangles). β-cateninlox/lox mice were crossed to mice carrying the IFN-α–inducible Mx-Cre transgene to inducibly inactivate β-catenin in the BM after pI-pC treatment. Arrows indicate approximate positions of the PCR primers used to verify the deletion of the floxed β-catenin locus. EcoRI restriction sites and the probe for Southern blot analysis are indicated. (b) Southern blot analysis of Eco-RI–digested genomic DNA from BM of WT, β-cateninlox/lox, or β-catenin−/− mice. The probe indicated in (a) reveals a 7-kb fragment for the WT allele, two fragments of 3.8 and 3.2 kb for the homozygously floxed β-catenin locus, and one 5.2-kb fragment for the β-catenin−/− allele after successful deletion of the loxP flanked gene segment. (c) Survival curve of β-cateninlox/lox and β-catenin−/− mice after injection of pI-pC as indicated by arrows. Death of β-catenin−/− mice starts 2 wk after the last injection. n = 8 for both β-cateninlox/lox (controls) and β-catenin−/−.
Mentions: Adult mice received five i.p. injections of 250 μg polyI-polyC (pI-pC; Sigma-Aldrich) at 2-d intervals. 2 d after the last injection, mice were killed and genomic DNA was prepared from BM cells using standard protocols. The deletion efficiency was assessed by Southern blot analysis of EcoRI-digested genomic DNA hybridized with a 7,000-bp EcoRI probe (see Fig. 1; reference 27) and quantified using a PhosphorImager (BAS-1000; Fuji).

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