Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified deletions at known DBA-related ribosomal protein gene loci in 17% (9/51) of patients without an identifiable mutation, including RPS19, RPS17, RPS26, and RPL35A
Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells. The samples compared are RNA extracted from CD71 positive erythroblasts sorted from the bone marrow of wild type mice and mice expressing a mutant RPS19 (RPS19R62W) transgene
Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells.
Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified deletions at known DBA-related ribosomal protein gene loci in 17% (9/51) of patients without an identifiable mutation, including RPS19, RPS17, RPS26, and RPL35A [Illumina platforms] A total of 68 samples were analyzed on Illumina Omni1_Quad or Illumina OmniExpress Genotyping bead arrays; 51 affected probands, 1 affected sibling, 1 unaffected sibling, and 15 parents. [NimbleGen platform] 5 samples where a deletion was identified by SNP array and one sample where no deletion was identified were run on Nimblegen Human CGH 3x720K Whole-Genome Exon-Focused arrays for confirmation.
Project description:This RNA sequencing experiment is part of the study "Preclinical animal model of Diamond-Blackfan anemia with single amino acid mutation of ribosomal protein Rps19". A mouse model with arginine 67 mutation of ribosomal protein Rps19 develops features characteristic of human Diamond-Blackfan anemia, a rare bone marrow failure syndrome. These include hematologic dysfunctions, early onset growth delay, intrinsic anemia, severe craniofacial, skeletal, urogenital, cardiovascular, and cerebral abnormalities leading to premature lethality during the adolescence of the mouse. This model exhibits cell intrinsic activation of the Trp53 signaling pathway in hematopoietic stem cells (HSCs) leading to reduced erythroid lineage development that may be rescued after inactivation of the tumor suppressor Trp53. Using preliminary RNA sequencing study we identify a set of non-canonical components of the p53 signaling pathway which with high likelihood mediate the wide range of pathologies associated with DBA, the experiment if followed up by single cell transcriptome analysis of bone marrow hematopoietic progenitors and RNA sequencing of E14.5 fetal liver from wild-type control and Rps19R67∆/R67∆, Rps19R67∆/R67∆ Trp53−/− and Trp53−/− mutant embryos.
Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified 2 patients with mosaic loss in the region of the the chromosome 5-deleted region involved in somatically-acquired 5q- myelodysplastic syndrome.
Project description:Transcriptome profile of highly purified multipotential (P), erythroid (E), and myeloid (M) bone marrow progenitors from three RPS19 mutated Diamond-Blackfan anemia and six control human subjects. Two group comparison of sex and age matched subjects. Bone marrow progenitors, gene expression profiling, Diamond-Blackfan anemia, RPS19
Project description:This RNA sequencing experiment is part of the study \\"Preclinical animal model of Diamond-Blackfan anemia with single amino acid mutation of ribosomal protein Rps19\\". A mouse model with conserved arginine 67 deletion of ribosomal protein Rps19 mutation develops features characteristic of human Diamond-Blackfan anemia, a rare bone marrow failure syndrome, including hematologic dysfunctions, early onset growth delay, intrinsic anemia, severe craniofacial, skeletal, urogenital, cardiovascular, and cerebral abnormalities leading to premature lethality during the adolescence of the mouse. This DBA mouse model exhibits cell intrinsic activation of the Trp53 signaling pathway in hematopoietic stem cells (HSCs) leading to reduced erythroid lineage development that may be rescued after inactivation of the tumor suppressor Trp53. The E14.5 fetal liver transcriptome analysis study confirms the involvement of non-canonical components of the p53 signaling pathway in the etiopathogenesis of DBA, manifested already during fetal development, consistent with the early onset of DBA-like phenotypes in mouse embryos as well as development of the disease in neonatal human patients. These results confirm our previous findings in adult hematopoietic progenitors as well as indicate that the development of DBA occurs well into the fetal development in both humans and our mouse model.
Project description:<p>In this study we have performed exome sequencing using the hybrid capture method that has previously been described (Gnirke et al., Nature Biotechnology, 2009) on genomic DNA samples from patients with the congenital bone marrow failure syndrome that affects the erythroid lineage, specifically, Diamond-Blackfan anemia. This disease is characterized by a hypoplastic anemia and approximately 50% of cases are attributable to mutations in ribosomal protein gene subunits. The other 50% of cases do not have a known genetic etiology and the purpose of this study is to attempt to delineate such causes.</p>