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Query: EC:2.7.10.1 (
ERK
)
95,504
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Hirschsprung disease (HSCR) is a congenital disorder characterised by intestinal obstruction due to an absence of intramural ganglia along variable lengths of the intestine.
RET
is the major gene involved in HSCR. Mutations in the
GDNF
gene, and encoding one of the
RET
ligands, either alone or in combination with
RET
mutations, can also cause HSCR, as can mutations in four other genes (EDN3, EDNRB, ECE1, and SOX10). The rare mutations in the latter four genes, however, are more or less restricted to HSCR associated with specific phenotypes. We have developed a novel comprehensive mutation detection system to analyse all but three amplicons of the
RET
and
GDNF
genes, based on denaturing gradient gel electrophoresis. We make use of two urea-formamide gradients on top of each other, allowing mutation detection over a broad range of melting temperatures. For the three remaining (GC-rich) PCR fragments we use a combination of DGGE and constant denaturing gel electrophoresis (CDGE). These two dual gel systems substantially facilitate mutation scanning of
RET
and
GDNF
, and may also serve as a model to develop mutation detection systems for other disease genes. In a screening of 95 HSCR patients,
RET
mutations were found in nine out of 17 familial cases (53%), all containing long segment HSCR. In 11 of 78 sporadic cases (14%), none had long segment HSCR. Only one
GDNF
mutation was found, in a sporadic case.
...
PMID:RET and GDNF gene scanning in Hirschsprung patients using two dual denaturing gel systems. 1079 Feb 3
The RET proto-oncogene encodes a receptor tyrosine kinase for transforming growth factor-beta-related neurotrophic factors, which include
GDNF
and neurturin. The expression of RET proto-oncogene was detected in several tissues, such as spleen, thymus, lymph nodes, salivary gland, and spinal cord, and in several neural crest-derived cell lines.
RET
expression in the thyroid gland was reported to be restricted to neural crest-derived C cells. The presence of
RET
mRNA or protein has not yet been reported in thyroid follicular cells. We previously demonstrated the expression of oncogenic rearranged versions of
RET
in papillary thyroid carcinomas: tumors derived from thyroid follicular cells. To assess the expression of the normal RET proto-oncogene in follicular cells, we analyzed its expression in a panel of neoplasias originating from thyroid follicular epithelial cells: papillary carcinomas and both follicular adenomas and carcinomas. We also demonstrated the presence of
RET
normal transcripts in two follicular thyroid carcinoma lymph node metastases. Moreover, we found the presence of the
RET
/ELE1 transcript, the reciprocal complementary form of the oncogenic fusion transcript ELE1/
RET
, in a papillary thyroid carcinoma specimen expressing the
RET
/PTC3 oncogene, thus demonstrating that the
RET
promoter is active in those cells after rearrangement. Finally, we show that in a papillary carcinoma-derived cell line expressing the proto-
RET
receptor and the related GFRalpha2 co-receptor,
GDNF
treatment induced
RET
tyrosine phosphorylation and subsequent signal transduction pathway, indicating that
RET
could be active in thyroid follicular cells.
...
PMID:RET receptor expression in thyroid follicular epithelial cell-derived tumors. 1085 Apr 26
Members of the
GDNF
protein family signal through receptors consisting of a GPI-linked GFRalpha subunit and the transmembrane tyrosine kinase Ret. Here we characterize the mouse Gfra4 and show that it undergoes developmentally regulated alternative splicing in several tissues. The mammalian GFRalpha4 receptor lacks the first Cys-rich domain characteristic of other GFRalpha receptors. Gfra4 is expressed in many tissues, including nervous system, in which intron retention leads to a putative intracellular or secreted GFRalpha4 protein. Efficient splicing occurs only in thyroid, parathyroid, and pituitary and less in adrenal glands. A splice form that leads to a GPI-linked GFRalpha4 receptor is expressed in juvenile thyroid and parathyroid glands. In newborn and mature thyroid as well as in parathyroid and pituitary glands major transcripts encode for a putative transmembrane isoform of GFRalpha4. Significant loss of thyroid C cells in Ret-deficient mice suggests that C cells and cells in adrenal medulla, which also express Ret, may require signaling via the GFRalpha4-Ret receptor. Finally, in human, GFRalpha4 expression may restrict the inherited cancer syndrome multiple endocrine neoplasia type 2, associated with mutations in
RET
, to these cells.
...
PMID:Expression and alternative splicing of mouse Gfra4 suggest roles in endocrine cell development. 1086 May 79
Hirschsprung disease, mental retardation, microcephaly, and specific craniofacial dysmorphism were observed in three children from a large, consanguineous, Moroccan family. A fourth child showed similar clinical features, with the exception of Hirschsprung disease. The association of these abnormalities in these children represents the Goldberg-Shprintzen syndrome (OMIM 235730). Mutation scanning of genes potentially involved in Hirschsprung disease,
RET
,
GDNF
, EDN3, and EDNRB, showed a sequence variant, Ser305Asn, in exon 4 of the EDNRB gene in the index patient of this family. The Ser305Asn substitution present in two of the four patients and four healthy relatives and absent in one of the remaining two patients illustrates the difficulties in interpreting the presence of mutations in families with Hirschsprung disease. It is unlikely that the EDNRB variant contributes to the phenotype. This consanguineous family might be useful for the identification of a Goldberg-Shprintzen locus.
...
PMID:A consanguineous family with Hirschsprung disease, microcephaly, and mental retardation (Goldberg-Shprintzen syndrome). 1087 40
Hirschsprung disease (HSCR) is characterized by the absence of intramural ganglion cells in the distal gut, resulting in bowel obstruction shortly after birth. Aganglionosis usually affects the distal colon, but may also extensively involve the entire colon and, rarely, the more proximal bowel. Recently, germline mutations of
RET
,
GDNF
, and NTN genes have been reported in HSCR. Here we describe the results of mutational analysis of these genes in 15 Japanese child patients with total colonic aganglionosis with small bowel involvement. DNA sequences of all the
RET
/
GDNF
/NTN coding regions were determined by the direct dyedeoxy terminator cycle method. Eight different
RET
mutations were identified in exons 1, 7, 10, 12, 15, and 17 in 10 of the 15 patients. Of these eight mutations, five were found in the tyrosine kinase domain. No
GDNF
or NTN mutation was found. Compared with typical HSCR, this patient group appeared to exhibit a higher percentage of
RET
mutations and accumulation of mutations in the tyrosine kinase domain. A homozygous (or hemizygous)
RET
mutation was found in a male baby with total intestinal aganglionosis, while the heterozygosity of the same mutation resulted in a less severe type of aganglionosis. In familial cases, all heterozygous for the same mutation, aganglionosis was more severe in male than in female siblings. These results also urge us to examine if the
RET
germline mutation may cause critical alteration of the
GDNF
/NTN-Ret signal transduction more severely in homo(hemi)zygosity and in male fetuses during organogenesis.
...
PMID:Mutational analysis of RET/GDNF/NTN genes in children with total colonic aganglionosis with small bowel involvement. 1094 53
Hirschsprung disease (HSCR; McKusick 142623) or aganglionic megacolon is a frequent (1 in 5,000 live births) heritable disorder of the enteric nervous system. By haplotyping with a variety of microsatellite markers, by amplifying all 20 exons of the RET proto-oncogene and by applying a direct DNA sequencing protocol, we have analyzed the DNA from HSCR patients in 6 different families. In one family with a joint occurrence of HSCR and FMTC (follicular medullary thyroid carcinoma), we have identified a mutation in codon 609 in one out of 6 cysteine residues encoded in exon 10 of the
RET
gene. This C609R point mutation has not previously been reported to cause HSCR. In 2 of the HSCR patients described here from different families, we have found a mutation in exon 2 (R77C) and a silent mutation in exon 3 (Y204Y), respectively, in the extracellular part of the RET proto-oncogene. In introns 2 and 17 of the RET proto-oncogene in 2 families, we have detected single nucleotide exchanges that are probably polymorphisms with unknown, if any, relations to HSCR. The DNA sequences of 5 further genes (
GDNF
, GDNFRalpha, EDN3, EDNRB, and NTN), that may contribute to the development of HSCR, have not shown mutations in the patients analyzed so far. In 2 of the reported families with several affected children and one grandchild, sequence analyses revealed no mutations in the coding regions of any of the candidate genes analyzed.
...
PMID:Familial form of hirschsprung disease: nucleotide sequence studies reveal point mutations in the RET proto-oncogene in two of six families but not in other candidate genes. 1098 77
The neurotrophic factors that influence the development and function of the parasympathetic branch of the autonomic nervous system are obscure. Recently, neurturin has been found to provide trophic support to neurons of the cranial parasympathetic ganglion. Here we show that
GDNF
signaling via the
RET
/GFR(alpha)1 complex is crucial for the development of cranial parasympathetic ganglia including the submandibular, sphenopalatine and otic ganglia.
GDNF
is required early for proliferation and/or migration of the neuronal precursors for the sphenopalatine and otic ganglia. Neurturin exerts its effect later and is required for further development and maintenance of these neurons. This switch in ligand dependency during development is at least partly governed by the altered expression of GFR(&agr;) receptors, as evidenced by the predominant expression of GFR(&agr;)2 in these neurons after ganglion formation.
...
PMID:Development of cranial parasympathetic ganglia requires sequential actions of GDNF and neurturin. 1104 2
Hirschsprung disease (HSCR), or congenital intestinal aganglionosis, is a relatively common disorder of neural crest migration. It has a strong genetic basis, although simple Mendelian inheritance is rarely observed. Hirschsprung disease is associated with several other anomalies and syndromes, and animal models for these conditions exist. Mutations in the
RET
gene are responsible for approximately half of familial cases and a smaller fraction of sporadic cases. Mutations in genes that encode
RET
ligands (
GDNF
and NTN); components of another signaling pathway (EDNRB, EDN3, ECE-1); and the transcription factor, SOX10, have been identified in HSCR patients. A subset of these mutations is associated with anomalies of pigmentation and/or hearing loss. For almost every HSCR gene, incomplete penetrance of the HSCR phenotype has been observed, probably due to genetic modifier loci. Thus, HSCR has become a model of a complex polygenic disorder in which the interplay of different genes is currently being elucidated.
...
PMID:Genetics of Hirschsprung disease. 1110 84
Mutations or rearrangements in the gene encoding the receptor tyrosine kinase
RET
result in Hirschsprung disease, cancer and renal malformations. The standard model of renal development involves reciprocal signaling between the ureteric bud epithelium, inducing metanephric mesenchyme to differentiate into nephrons, and metanephric mesenchyme, inducing the ureteric bud to grow and branch.
RET
and
GDNF
(a
RET
ligand) are essential mediators of these epithelial-mesenchymal interactions. Vitamin A deficiency has been associated with widespread embryonic abnormalities, including renal malformations. The vitamin A signal is transduced by nuclear retinoic acid receptors (RARs). We previously showed that two RAR genes, Rara and Rarb2, were colocalized in stromal mesenchyme, a third renal cell type, where their deletion led to altered stromal cell patterning, impaired ureteric bud growth and downregulation of Ret in the ureteric bud. Here we demonstrate that forced expression of Ret in mice deficient for both Rara and Rarb2 (Rara(-/-)Rarb2(-/-)) genetically rescues renal development, restoring ureteric bud growth and stromal cell patterning. Our studies indicate the presence of a new reciprocal signaling loop between the ureteric bud epithelium and the stromal mesenchyme, dependent on Ret and vitamin A. In the first part of the loop, vitamin-A-dependent signals secreted by stromal cells control Ret expression in the ureteric bud. In the second part of the loop, ureteric bud signals dependent on Ret control stromal cell patterning.
...
PMID:Vitamin A controls epithelial/mesenchymal interactions through Ret expression. 1113 2
Hirschsprung's disease (HSCR, aganglionic megacolon) is a frequent congenital malformation regarded as a multigenic neurocristopathy. Three susceptibility genes have been recently identified in HSCR, namely the RET proto-oncogene, the endothelin B receptor (EDNRB) gene, and the endothelin 3 (EDN3) gene.
RET
gene mutations were found in significant proportions of familial (50%) and sporadic (15-20%) HSCR, while homozygosity for EDNRB or EDN3 mutations accounted for the rare HSCR-Waardenburg syndrome (WS) association. More recently, heterozygous EDNRB an EDN3 missense mutations have been reported in isolated HSCR patients. Some of these results were obtained after the identification of mouse genes whose natural or site-directed mutations resulted in megacolon and coat color spotting. There is also conclusive evidence for the involvement of other independent loci in HSCR. In particular, the recent identification of neurotrophic factors acting as
RET
ligands (
GDNF
and Neurturin) provide additional candidate genes for HSCR. The dissection of the genetic etiology of HSCR disease may then provide a unique opportunity to distinguish between a polygenic and a genetically heterogeneous disease, thereby helping to understand other complex disorders and congenital malformations hitherto considered as multifactorial in origin. Finally, the study of the molecular bases of HSCR is also a step towards the understanding of developmental genetics of the enteric nervous system giving support to the role of the tyrosine kinase and endothelin-signaling pathways in the development of neural crest-derived enteric neurons in human.
...
PMID:[Molecular genetics of Hirschsprung disease: a model of multigenic neurocristopathy]. 1132 13
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