The DiGeorge anomaly as a developmental field defect

Lammer, Edward J.; Opitz, John M.

doi:10.1002/ajmg.1320250615

Cited by 191 publications

(78 citation statements)

References 54 publications

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“…In this study, we focus on how retinoic acid (RA) signaling influences endodermal pouch development at different embryonic stages. It is understood that RA affects pharyngeal arch development because of the phenotypes observed in infants whose mothers were exposed to high levels of Vitamin A during pregnancy (Lammer and Opitz, 1986;de Die-Smulders et al, 1995). In addition, these defects can be phenocopied by treating pregnant experimental animals with vitamin A (a precursor of RA) or synthetic RA (Kalter and Warkany, 1961;Shenefelt, 1972;Fantel et al, 1977;Davis and Sadler, 1981;Scambler, 2000).…”

Section: Introductionmentioning

confidence: 99%

Retinoic acid is required for endodermal pouch morphogenesis and not for pharyngeal endoderm specification

Kopinke

Sasine

Swift

et al. 2006

Developmental Dynamics

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Because tissues from all three germ layers contribute to the pharyngeal arches, it is not surprising that all major signaling pathways are involved in their development. We focus on the role of retinoic acid (RA) signaling because it has been recognized for quite some time that alterations in this pathway lead to craniofacial malformations. Several studies exist that describe phenotypes observed upon RA perturbations in pharyngeal arch development; however, these studies did not address whether RA plays multiple roles at distinct time points during development. Here, we report the resulting phenotypes in the hindbrain, the neural crest-derived tissues, and the pharyngeal endoderm when RA synthesis is disrupted during zebrafish gastrulation and pharyngeal arch morphogenesis. Our results demonstrate that RA is required for the postgastrulation morphogenesis and segmentation of endodermal pouches, and that loss of RA does not affect the length of the pharyngeal ectoderm or medial endoderm along the anterior-posterior axis. We also provide evidence that RA is not required for the specification of pharyngeal pouch endoderm and that the pharyngeal endoderm consists of at least two different cell populations, of which the pouch endoderm is sensitive to RA and the more medial pharyngeal endoderm is not. These results demonstrate that the developmental processes underlying pharyngeal arch defects differ depending on when RA signaling is disturbed during development.

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Section: Introductionmentioning

confidence: 99%

Retinoic acid is required for endodermal pouch morphogenesis and not for pharyngeal endoderm specification

Kopinke

Sasine

Swift

et al. 2006

Developmental Dynamics

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“…It is characterised by an absent or hypoplastic thymus with T-cell deficiency, absent or hypoplastic parathyroid glands with hypoparathyroidism and hypocalcaemia, conotruncal heart defect, craniofacial dysmorphism, and mental retardation. 1,2 More than 90% of patients with DGS have a microdeletion of 22q11 (DGS1). 3,4 The associated phenotypes are variable, with a large proportion of patients exhibiting only a subset of the above mentioned traits.…”

Section: Introductionmentioning

confidence: 99%

“…6,7 Several candidate genes from the 22q11 deletion region have been cloned, but no genotype-phenotype correlation has emerged so far. [8][9][10][11][12] The etiology of DGS is heterogeneous and includes teratogens such as alcohol or retinoids 1 and chromosomal abnormalities, for instance partial monosomies, [13][14][15][16][17] partial trisomies, [18][19][20][21][22] and mosaic tetrasomy. 23 Most of these cases represent single reports of DGS associated with a specific chromosomal aberration, with the exception of partial monosomy 10p where ten cases have so far been described.…”

Section: Introductionmentioning

confidence: 99%

Deletion mapping on chromosome 10p and definition of a critical region for the second DiGeorge syndrome locus (DGS2)

et al. 1998

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DiGeorge syndrome (DGS) is a developmental field defect, characterised by absent/hypoplastic thymus and parathyroid, and conotruncal heart defects, with haploinsufficiency loci at 22q (DGS1) and 10p (DGS2). We performed fluorescence in situ hybridisations (FISH) and polymerase chain reaction (PCR) analyses in 12 patients with 10p deletions, nine of them with features of DGS, and in a familial translocation 10p;14q associated with midline defects. The critical DGS2 region is defined by two DGS patients, and maps within a 1 cM interval including D10S547 and D10S585. The other seven DGS patients are hemizygous for both loci. The breakpoint of the reciprocal translocation 10p;14q maps at a distance of at least 12 cM distal to the critical DGS2 region. Interstitial and terminal deletions described are in the range of 10-50 cM and enable the tentative mapping of loci for ptosis and hearing loss, features which are not part of the DGS clinical spectrum.

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“…The human HIRA protein is encoded by a gene within a region of chromosome 22q11.2 deleted in most patients with the developmental condition known as DiGeorge syndrome or velocardiofacial syndrome (Halford et al 1993). In such patients, certain organs and tissues derived from neural crest cells in the pharyngeal region of the developing embryo are affected (Lammer and Opitz 1986). In contrast to S. cerevisiae, the human homolog HIRA encodes a protein that encompasses structural features of both yeast Hir1 and Hir2 proteins as a single polypeptide (Lamour et al 1995).…”

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confidence: 99%

The HIR corepressor complex binds to nucleosomes generating a distinct protein/DNA complex resistant to remodeling by SWI/SNF

Prochasson¹,

Florens²,

Swanson³

et al. 2005

Genes Dev.

101

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The histone regulatory (HIR) and histone promoter control (HPC) repressor proteins regulate three of the four histone gene loci during the Saccharomyces cerevisiae cell cycle. Here, we demonstrate that Hir1, Hir2, Hir3, and Hpc2 proteins form a stable HIR repressor complex. The HIR complex promotes histone deposition onto DNA in vitro and constitutes a novel nucleosome assembly complex. The HIR complex stably binds to DNA and nucleosomes. Furthermore, HIR complex binding to nucleosomes forms a distinct protein/DNA complex resistant to remodeling by SWI/SNF. Thus, the HIR complex is a novel nucleosome assembly complex which functions with SWI/SNF to regulate transcription. Histone gene transcription is tightly regulated during cell cycle progression and coordinated with DNA replication in eukaryotes. Six of the eight histone genes (HTA1-HTB1, HHT1-HHF1, and HHT2-HHF2) are negatively regulated through a site present in their promoter close to upstream activation sequence (UAS) elements (Osley et al. 1986;Freeman et al. 1992). Histone gene transcription is repressed outside of the G1/S in Saccharomyces cerevisiae. Several trans-acting factors that act at the negative site to repress transcription were identified through genetic screens Xu et al. 1992). Some of these factors, the histone regulatory (HIR) genes including HIR1, HIR2, HIR3, and the histone promoter control (HPC) gene HPC2, are transcriptional corepressors that are not thought to possess intrinsic DNA-binding activity Xu et al. 1992;Sherwood et al. 1993;Lamour et al. 1995). However, both Hir1 and Hir2 associate with the HTA1-HTB1 regulatory domain, although there is no evidence that the Hir proteins bind directly to the cis-acting site required for the repression of the histone genes (Dimova et al. 1999;Sutton et al. 2001). The Hir proteins are postulated to be recruited to the negative site by a yet unidentified sequence-specific binding factor, and once at this site directly repress transcription (Spector et al. 1997;DeSilva et al. 1998). The mechanism by which Hir/Hpc proteins repress histone gene transcription is not clear, but is likely to involve the modulation of chromatin structure. The Hir corepressors interact with the SWI/SNF chromatin-remodeling complex and are required for its recruitment to the HTA1-HTB1 promoter (Dimova et al. 1999).The yeast multisubunit SWI/SNF complex is an ATPdependent chromatin-remodeling complex that can mobilize nucleosomes for activation or repression of a subset of yeast genes (Wang 2003;Lee et al. 2004). The SWI/ SNF complex can be recruited to specific promoters through a variety of mechanisms, one of which is through direct interaction with sequence-specific transcriptional activators. We previously showed that activator-interaction domains within the Snf5 and Swi1 subunits play a critical role in the promoter targeting of SWI/SNF, which is essential for its function in vivo (Prochasson et al. 2003).Deletion analysis of SWI/SNF subunits demonstrates that they are required for maximal expression of the histone ...

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The DiGeorge anomaly as a developmental field defect

Cited by 191 publications

References 54 publications

Retinoic acid is required for endodermal pouch morphogenesis and not for pharyngeal endoderm specification

Retinoic acid is required for endodermal pouch morphogenesis and not for pharyngeal endoderm specification

Deletion mapping on chromosome 10p and definition of a critical region for the second DiGeorge syndrome locus (DGS2)

The HIR corepressor complex binds to nucleosomes generating a distinct protein/DNA complex resistant to remodeling by SWI/SNF

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