Limits...
Role of chromodomain helicase DNA-binding protein 2 in DNA damage response signaling and tumorigenesis.

Nagarajan P, Onami TM, Rajagopalan S, Kania S, Donnell R, Venkatachalam S - Oncogene (2009)

Bottom Line: The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation.Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression.At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, gamma H2AX, and exhibit an aberrant DNA damage response after X-ray irradiation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.

ABSTRACT
The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation. In an effort to understand the functional role of the CHD2 in mammals, we have generated a Chd2 mutant mouse model. Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression. The Chd2 heterozygous mutant mice exhibit increased extramedullary hematopoiesis and susceptibility to lymphomas. At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, gamma H2AX, and exhibit an aberrant DNA damage response after X-ray irradiation. Our data suggest a direct role for the chromatin remodeling protein in DNA damage signaling and genome stability maintenance.

Show MeSH

Related in: MedlinePlus

Analysis of developmental phenotypes in Chd2 mutant micea, Morphological phenotypes of Chd2 mutant embryos. E12.5 embryos were harvested and photographed. b, Hematopoietic cell distribution and organization defects in mutant neonates. Representative images of hemotoxylin and eosin (H&E) stained sections of WT and homozygous mutant neonatal liver sections are shown. The megakaryocytes are circled. c, Increased megakaryocytes in Chd2 mutant mice. A total of 10 different fields were counted from hematoxylin and eosin stained sections of neonatal fetal livers from each group (n=7). The differences between the wild-type and the mutants were statistically significant as determined by single tailed t-test (WT v. +/m P<0.002 and WT v. m/m P<0.005). Error bars represent s.e. d, Hematopoietic stem cell differentiation defects in Chd2 mutants. Burst forming unit —erythroid (BFU-E) and Colony-forming unit-granulocyte macrophage (CFU-GM) formation in wild-type (n=5), Chd2+/m (n=5) and Chd2m/m (n=8) were assayed using E13.5 fetal liver progenitor cells as described. The differences between the wild-type and the homozygous mutants were statistically significant as determined by single tailed t-test (WT v. m/m P<0.00005). Error bars represent s.e.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2648865&req=5

Figure 1: Analysis of developmental phenotypes in Chd2 mutant micea, Morphological phenotypes of Chd2 mutant embryos. E12.5 embryos were harvested and photographed. b, Hematopoietic cell distribution and organization defects in mutant neonates. Representative images of hemotoxylin and eosin (H&E) stained sections of WT and homozygous mutant neonatal liver sections are shown. The megakaryocytes are circled. c, Increased megakaryocytes in Chd2 mutant mice. A total of 10 different fields were counted from hematoxylin and eosin stained sections of neonatal fetal livers from each group (n=7). The differences between the wild-type and the mutants were statistically significant as determined by single tailed t-test (WT v. +/m P<0.002 and WT v. m/m P<0.005). Error bars represent s.e. d, Hematopoietic stem cell differentiation defects in Chd2 mutants. Burst forming unit —erythroid (BFU-E) and Colony-forming unit-granulocyte macrophage (CFU-GM) formation in wild-type (n=5), Chd2+/m (n=5) and Chd2m/m (n=8) were assayed using E13.5 fetal liver progenitor cells as described. The differences between the wild-type and the homozygous mutants were statistically significant as determined by single tailed t-test (WT v. m/m P<0.00005). Error bars represent s.e.

Mentions: In an effort to understand the role of Chd2 in mammalian development and physiology, we generated a Chd2 mutant mouse model using the Baygenomics gene trap ES cell resource [Supplementary information and supplementary figure 1] (Stryke et al., 2003). Genotype analysis of the embryos and offspring obtained from F1 heterozygous intercrosses indicated that the Chd2 mutation led to embryonic and perinatal lethality (data not shown). Interestingly, the proportion of heterozygotes obtained from the intercrosses was also less than the expected 2:1 ratio of the total offspring and this was further confirmed in crosses between heterozygous males and wild type females (Supplementary Table 1). Morphological analysis of the heterozygous and homozygous mutant embryos at E12.5 revealed a drastic reduction in the formation of vascular structures and regions of localized hemorrhaging (Fig. 1a). Further analysis of the reduced vasculature of the Chd2 homozygous mutant embryos showed a substantial decrease in PECAM-1 staining in the peripheral vascular structures indicative of defective vascular wall integrity in a subset set of mutants (data not shown). Interestingly, the hemorrhages were also present in some of the heterozygous mutants and this could explain the partial lethality of the heterozygous animals.


Role of chromodomain helicase DNA-binding protein 2 in DNA damage response signaling and tumorigenesis.

Nagarajan P, Onami TM, Rajagopalan S, Kania S, Donnell R, Venkatachalam S - Oncogene (2009)

Analysis of developmental phenotypes in Chd2 mutant micea, Morphological phenotypes of Chd2 mutant embryos. E12.5 embryos were harvested and photographed. b, Hematopoietic cell distribution and organization defects in mutant neonates. Representative images of hemotoxylin and eosin (H&E) stained sections of WT and homozygous mutant neonatal liver sections are shown. The megakaryocytes are circled. c, Increased megakaryocytes in Chd2 mutant mice. A total of 10 different fields were counted from hematoxylin and eosin stained sections of neonatal fetal livers from each group (n=7). The differences between the wild-type and the mutants were statistically significant as determined by single tailed t-test (WT v. +/m P<0.002 and WT v. m/m P<0.005). Error bars represent s.e. d, Hematopoietic stem cell differentiation defects in Chd2 mutants. Burst forming unit —erythroid (BFU-E) and Colony-forming unit-granulocyte macrophage (CFU-GM) formation in wild-type (n=5), Chd2+/m (n=5) and Chd2m/m (n=8) were assayed using E13.5 fetal liver progenitor cells as described. The differences between the wild-type and the homozygous mutants were statistically significant as determined by single tailed t-test (WT v. m/m P<0.00005). Error bars represent s.e.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2648865&req=5

Figure 1: Analysis of developmental phenotypes in Chd2 mutant micea, Morphological phenotypes of Chd2 mutant embryos. E12.5 embryos were harvested and photographed. b, Hematopoietic cell distribution and organization defects in mutant neonates. Representative images of hemotoxylin and eosin (H&E) stained sections of WT and homozygous mutant neonatal liver sections are shown. The megakaryocytes are circled. c, Increased megakaryocytes in Chd2 mutant mice. A total of 10 different fields were counted from hematoxylin and eosin stained sections of neonatal fetal livers from each group (n=7). The differences between the wild-type and the mutants were statistically significant as determined by single tailed t-test (WT v. +/m P<0.002 and WT v. m/m P<0.005). Error bars represent s.e. d, Hematopoietic stem cell differentiation defects in Chd2 mutants. Burst forming unit —erythroid (BFU-E) and Colony-forming unit-granulocyte macrophage (CFU-GM) formation in wild-type (n=5), Chd2+/m (n=5) and Chd2m/m (n=8) were assayed using E13.5 fetal liver progenitor cells as described. The differences between the wild-type and the homozygous mutants were statistically significant as determined by single tailed t-test (WT v. m/m P<0.00005). Error bars represent s.e.
Mentions: In an effort to understand the role of Chd2 in mammalian development and physiology, we generated a Chd2 mutant mouse model using the Baygenomics gene trap ES cell resource [Supplementary information and supplementary figure 1] (Stryke et al., 2003). Genotype analysis of the embryos and offspring obtained from F1 heterozygous intercrosses indicated that the Chd2 mutation led to embryonic and perinatal lethality (data not shown). Interestingly, the proportion of heterozygotes obtained from the intercrosses was also less than the expected 2:1 ratio of the total offspring and this was further confirmed in crosses between heterozygous males and wild type females (Supplementary Table 1). Morphological analysis of the heterozygous and homozygous mutant embryos at E12.5 revealed a drastic reduction in the formation of vascular structures and regions of localized hemorrhaging (Fig. 1a). Further analysis of the reduced vasculature of the Chd2 homozygous mutant embryos showed a substantial decrease in PECAM-1 staining in the peripheral vascular structures indicative of defective vascular wall integrity in a subset set of mutants (data not shown). Interestingly, the hemorrhages were also present in some of the heterozygous mutants and this could explain the partial lethality of the heterozygous animals.

Bottom Line: The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation.Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression.At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, gamma H2AX, and exhibit an aberrant DNA damage response after X-ray irradiation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.

ABSTRACT
The chromodomain helicase DNA-binding proteins (CHDs) are known to affect transcription through their ability to remodel chromatin and modulate histone deacetylation. In an effort to understand the functional role of the CHD2 in mammals, we have generated a Chd2 mutant mouse model. Remarkably, the Chd2 protein appears to play a critical role in the development, hematopoiesis and tumor suppression. The Chd2 heterozygous mutant mice exhibit increased extramedullary hematopoiesis and susceptibility to lymphomas. At the cellular level, Chd2 mutants are defective in hematopoietic stem cell differentiation, accumulate higher levels of the chromatin-associated DNA damage response mediator, gamma H2AX, and exhibit an aberrant DNA damage response after X-ray irradiation. Our data suggest a direct role for the chromatin remodeling protein in DNA damage signaling and genome stability maintenance.

Show MeSH
Related in: MedlinePlus