Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genomic DNAs from twelve Japanese patients with steroid 21-hydroxylase [21-OHase; steroid 21-monooxygenase; steroid, hydrogen-donor:oxygen oxidoreductase (21-hydroxylating); EC 1.14.99.10] deficiency were analyzed by Southern blot hybridization. A 3.7-kilobase (kb) Taq I and a 1.7-kb Pvu II restriction endonuclease fragment that correspond to a 21-OHase B gene were absent from the DNA of two unrelated patients with the salt-wasting form of the disease. However, a 10.5-kb Bgl II fragment corresponding to the region encompassing the 21-OHase B gene was still present in these two patients. The genes encoding 21-OHase were cloned from one of these two patients, who was homozygous by descent for HLA-A26;B39;C4A3;C4B1;DR4. Restriction endonuclease mapping as well as partial nucleotide sequencing analysis revealed that the 21-OHase B gene of the patient has been converted to the pseudogene, 21-OHase A, as far as the critical 0.5-kb sequence was concerned. Thus, the defect was due to both chromosomes each carrying two copies of 21-OHase A pseudogene and lacking functional 21-OHase B gene.
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PMID:Gene conversion-like events cause steroid 21-hydroxylase deficiency in congenital adrenal hyperplasia. 350 Apr 73

We have determined the molecular genetic basis of congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency. This common disorder of cortisol biosynthesis is HLA-linked. The haplotype HLA-(A3);Bw47;DR7 is strongly associated with 21-OHase deficiency and always carries a null allele at the locus encoding the C4A (Rodgers) form of the fourth component (C4) of complement. It seemed likely that this haplotype carries a deletion encompassing the genes encoding both C4A and 21-OHase. We hypothesized that the HLA-linked defect involved a structural gene for the adrenal microsomal cytochrome P-450 specific for steroid 21-hydroxylation. Using a plasmid with a 520-base-pair bovine adrenal cDNA insert encoding the middle third of the cytochrome P-450 polypeptide, we compared hybridization patterns in DNA from normal and 21-OHase-deficient individuals. Normal human DNA yielded two fragments that hybridized with the probe after digestion with either restriction endonuclease EcoRI [12- and 14-kilobase (kb) fragments] or Taq I (3.7 and 3.2 kb). One of these bands (the first mentioned in each digest) was absent in DNA from a cell line derived from a patient homozygous for HLA-Bw47. DNA from six unrelated patients homozygous for 21-OHase deficiency who were heterozygous for HLA-Bw47 yielded diminished relative intensity of the 3.7-kb Taq I band in five patients, consistent with a heterozygous deletion, and complete disappearance of the 3.7-kb band in one. This deletion segregated with HLA-Bw47 in a large pedigree carrying 21-OHase deficiency and HLA-Bw47. Thus, 21-OHase deficiency sometimes results from the deletion of a specific cytochrome P-450 gene and sometimes, presumably, from smaller mutations. This gene is probably located very near the C4A gene.
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PMID:HLA-linked congenital adrenal hyperplasia results from a defective gene encoding a cytochrome P-450 specific for steroid 21-hydroxylation. 633 10

Congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency is HLA-linked. The haplotype HLA-(A3);Bw47;DR7 is strongly associated with 21-OH deficiency and always carries a null allele at the complement C4A (Rodgers) locus. It seemed likely that this haplotype carries a deletion encompassing both the C4A and 21-OH loci. We hypothesized that the HLA-linked defect involved a structural gene for the adrenal microsomal cytochrome P-450 specific for steroid 21-hydroxylation. We isolated a plasmid with a 520 bp bovine adrenal cDNA insert encoding the middle third of the P-450 peptide. When human DNA was digested with Taq I restriction endonuclease and hybridized with the cDNA probe, DNA from 13 unrelated normal individuals yielded two hybridizing bands of equal intensity at 3.7 and 3.2 kb. The upper band was not present in DNA from a patient homozygous for Bw47. DNA from six unrelated patients heterozygous for Bw47 yielded, in five, diminished relative intensity of the upper band consistent with a heterozygous deletion, and complete disappearance of the upper band in one. Thus 21-OH deficiency sometimes results from the deletion of a gene and sometimes, presumably, from smaller mutations. This gene is probably located very near the C4A gene encoding the 4th component of complement.
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PMID:Molecular cloning of steroid 21-hydroxylase. 633 60


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