Project description:Rationale: 22q11 deletion syndrome arises from recombination between low copy repeats on chromosome 22. Typical deletions result in hemizygosity for TBX1 associated with congenital cardiovascular disease. Deletions distal to the typically deleted region result in a similar cardiac phenotype but lack extra-cardiac features of the syndrome suggesting that a second haploinsufficient gene maps to this interval. Objective: The transcription factor HIC2 is lost in most distal deletions as well as a minority of typical deletions. We used mouse models to test the hypothesis that HIC2 hemizygosity causes congenital heart disease. Methods and Results: We created a genetrap mouse allele of Hic2. The genetrap reporter was expressed in the heart throughout the key stages of cardiac morphogenesis. Homozygosity for the genetrap allele was embryonic lethal before embryonic day E10.5 while the heterozygous condition exhibited a partially penetrant late lethality. One third of heterozygous embryos had a cardiac phenotype. Magnetic resonance imaging demonstrated a ventricular septal defect with overriding aorta. Conditional targeting indicated a requirement for Hic2 within the Nkx2.5+ and Mesp1+ cardiovascular progenitor lineages but not in the Wnt1+ neural crest or Mef2c+ second heart field lineages. Microarray analysis revealed increased expression of BMP10. Conclusions: Our results demonstrate a novel role for Hic2 in cardiac development. Hic2 is the first gene within the distal 22q11 interval to have a demonstrated haploinsufficient cardiac phenotype in mice. Together our data suggests HIC2 haploinsufficiency likely contributes to the cardiac defects seen in distal 22q11 deletion syndrome. The aim of this microarray experiment was to compare gene expression changes in the E13.5 mouse heart in a conditional knockout of Hic2 (Mesp1Cre/+; Hic2FL/FL) against control. All samples represent pools of isolated hearts from E13.5 mouse embryos. 3 replicates of each genotype were assayed. The genotypes are: 'WT' (Hic2FL/FL) 'KO' (Mesp1Cre/+; Hic2 FL/FL)
Project description:Rationale: 22q11 deletion syndrome arises from recombination between low copy repeats on chromosome 22. Typical deletions result in hemizygosity for TBX1 associated with congenital cardiovascular disease. Deletions distal to the typically deleted region result in a similar cardiac phenotype but lack extra-cardiac features of the syndrome suggesting that a second haploinsufficient gene maps to this interval. Objective: The transcription factor HIC2 is lost in most distal deletions as well as a minority of typical deletions. We used mouse models to test the hypothesis that HIC2 hemizygosity causes congenital heart disease. Methods and Results: We created a genetrap mouse allele of Hic2. The genetrap reporter was expressed in the heart throughout the key stages of cardiac morphogenesis. Homozygosity for the genetrap allele was embryonic lethal before embryonic day E10.5 while the heterozygous condition exhibited a partially penetrant late lethality. One third of heterozygous embryos had a cardiac phenotype. Magnetic resonance imaging demonstrated a ventricular septal defect with overriding aorta. Conditional targeting indicated a requirement for Hic2 within the Nkx2.5+ and Mesp1+ cardiovascular progenitor lineages but not in the Wnt1+ neural crest or Mef2c+ second heart field lineages. Microarray analysis revealed increased expression of BMP10. Conclusions: Our results demonstrate a novel role for Hic2 in cardiac development. Hic2 is the first gene within the distal 22q11 interval to have a demonstrated haploinsufficient cardiac phenotype in mice. Together our data suggests HIC2 haploinsufficiency likely contributes to the cardiac defects seen in distal 22q11 deletion syndrome. the aim of this microarray experiment was to compare gene expression changes in the E13.5 mouse heart in a conditional knockout of Hic2 (Mesp1Cre/+; Hic2FL/FL) against control.
Project description:22q11-deletion syndrome (22q11DS) is a developmental anomaly caused by a microdeletion on human chromosome 22q11. Although mouse models indicated Tbx1 as the gene responsible of the syndrome, the phenotypic spectrum of del22q11 patients is complex suggesting that gene-gene and gene-environment interactions, probably during embryonic development, are crucial in delineating the pathogenesis of 22q11DS. In order to define cis-acting regulatory effects of 22q11Ds haploinsufficiency during development we analysed the expression pattern of MM16 mouse genes, that is the syntenic region to 22q11, in RNA from total embryos at different stages (from 4.5 dpc to 14.5 dpc; corresponding to pharyngeal development) by a low density microarray (22q11DS-chip). Keywords: time-course
Project description:Purpose: 22q11 Deletion Syndrome (22q11DS) is a disorder caused by a heterozygous deletion of 3 million base pairs containing approximately 50 known genes on chromosome 22q. It occurs in around 1 in 4,000 live births. The common phenotypes of 22q11DS include a large spectrum of congenital anomalies, most notably of the cardiovascular system as well as several developmental neuropsychiatric disorders, in particular schizophrenia and autism spectrum disorders.Here we are testing the hypothesis that, in addition to changing the gene dosage of genes located within the CNV boundaries, large CNVs may have an effect on long-range chromosome interactions and epigenetic profiles. Methods: We generated Hi-C contact maps for 11 human lymphoblastoid cell lines and performed RNA-Seq on 14 cell lines and ChIP-seq of H3K27ac, H3K27me3 and CTCF for some of the cell lines. Results: We found dosage effects of 22q11del on chromosome contacts, epigenetic profiles and gene expressions. Extensive changes on these levels caused by 22q11del are global instead of confined to the deletion region only. Conclusions: Our results shed light on the comprehensive effects of 22q11del on different molecular levels in lymphoblastoid cell lines.
Project description:We report a recurrent microdeletion syndrome causing mental retardation, epilepsy and variable facial and digital dysmorphisms. We describe nine patients, including six probands; two with de novo deletions, two who inherited the deletion from an affected parent, and two with unknown inheritance. The proximal breakpoint of the largest deletion is contiguous with breakpoint 3 (BP3) of the Prader-Willi/Angelman region extending 3.95 Mb distally to BP5. A smaller 1.5 Mb deletion has proximal breakpoint within the larger deletion (BP4) and shares the same distal BP5. This recurrent 1.5 Mb deletion contains six genes, including a candidate gene for epilepsy (CHRNA7) that is likely responsible for the observed seizure phenotype. The BP4-BP5 region undergoes frequent inversion, suggesting a possible link between this inversion polymorphism and recurrent deletion. The frequency of these microdeletions in mental retardation cases is ~0.3% (6/2082 tested), a prevalence comparable to that of the Williams, Angelman, and Prader-Willi syndromes. Keywords: microdeletion, genomic disorder, mental retardation, epilepsy Patients were intially screened by BAC array CGH (n=290) or qPCR (n=1040). Patients with potential 15q13 deletions were then analyzed on a custom oligonucleotide array targeted to the 15q13 region, results of which are shown here.
Project description:The fetal hemoglobin (HBG) regulator BCL11A is repressed by HIC2 to regulate hemoglobin switching. HIC2 itself is under developmental control, highly expressed in fetal tissues and decreased in adult cells, but the mechanism of this developmental regulation is unclear. Here, we demonstrate that HIC2 is developmentally controlled by miRNAs, and loss of global miRNA biogenesis through DICER1 depletion leads to upregulation of HIC2 and HBG. We subsequently identify the adult-expressed let-7 miRNA family as a repressor of HIC2 expression. Ectopic expression of let-7 in fetal-type cells repressed HIC2 levels, while let-7 inhibition in adult erythroblasts upregulated HIC2 levels. Let-7 regulates BCL11A and HBG through induction of HIC2 and reduction of GATA1 binding at the BCL11A erythroid enhancer. Finally, HIC2 depletion rescues BCL11A-mediated repression of fetal hemoglobin in let-7 inhibited cells. Together these data demonstrate a key miRNA-mediated mechanism for developmental regulation of BCL11A expression and fetal hemoglobin repression in adult erythroid cells.
Project description:The fetal hemoglobin (HBG) regulator BCL11A is repressed by HIC2 to regulate hemoglobin switching. HIC2 itself is under developmental control, highly expressed in fetal tissues and decreased in adult cells, but the mechanism of this developmental regulation is unclear. Here, we demonstrate that HIC2 is developmentally controlled by miRNAs, and loss of global miRNA biogenesis through DICER1 depletion leads to upregulation of HIC2 and HBG. We subsequently identify the adult-expressed let-7 miRNA family as a repressor of HIC2 expression. Ectopic expression of let-7 in fetal-type cells repressed HIC2 levels, while let-7 inhibition in adult erythroblasts upregulated HIC2 levels. Let-7 regulates BCL11A and HBG through induction of HIC2 and reduction of GATA1 binding at the BCL11A erythroid enhancer. Finally, HIC2 depletion rescues BCL11A-mediated repression of fetal hemoglobin in let-7 inhibited cells. Together these data demonstrate a key miRNA-mediated mechanism for developmental regulation of BCL11A expression and fetal hemoglobin repression in adult erythroid cells.
Project description:The fetal hemoglobin (HBG) regulator BCL11A is repressed by HIC2 to regulate hemoglobin switching. HIC2 itself is under developmental control, highly expressed in fetal tissues and decreased in adult cells, but the mechanism of this developmental regulation is unclear. Here, we demonstrate that HIC2 is developmentally controlled by miRNAs, and loss of global miRNA biogenesis through DICER1 depletion leads to upregulation of HIC2 and HBG. We subsequently identify the adult-expressed let-7 miRNA family as a repressor of HIC2 expression. Ectopic expression of let-7 in fetal-type cells repressed HIC2 levels, while let-7 inhibition in adult erythroblasts upregulated HIC2 levels. Let-7 regulates BCL11A and HBG through induction of HIC2 and reduction of GATA1 binding at the BCL11A erythroid enhancer. Finally, HIC2 depletion rescues BCL11A-mediated repression of fetal hemoglobin in let-7 inhibited cells. Together these data demonstrate a key miRNA-mediated mechanism for developmental regulation of BCL11A expression and fetal hemoglobin repression in adult erythroid cells.
Project description:The fetal hemoglobin (HBG) regulator BCL11A is repressed by HIC2 to regulate hemoglobin switching. HIC2 itself is under developmental control, highly expressed in fetal tissues and decreased in adult cells, but the mechanism of this developmental regulation is unclear. Here, we demonstrate that HIC2 is developmentally controlled by miRNAs, and loss of global miRNA biogenesis through DICER1 depletion leads to upregulation of HIC2 and HBG. We subsequently identify the adult-expressed let-7 miRNA family as a repressor of HIC2 expression. Ectopic expression of let-7 in fetal-type cells repressed HIC2 levels, while let-7 inhibition in adult erythroblasts upregulated HIC2 levels. Let-7 regulates BCL11A and HBG through induction of HIC2 and reduction of GATA1 binding at the BCL11A erythroid enhancer. Finally, HIC2 depletion rescues BCL11A-mediated repression of fetal hemoglobin in let-7 inhibited cells. Together these data demonstrate a key miRNA-mediated mechanism for developmental regulation of BCL11A expression and fetal hemoglobin repression in adult erythroid cells.