Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Hpa I restriction endonuclease site polymorphism that results in some human beta globin genes being contained in a 13-kilobase (kb) DNA restriction fragment rather than in the usual 7.6-kb fragment has been reported to be in linkage disequilibrium with the beta S mutation. The frequency of the 13-kb fragment among Baltimore black sickle cell (SS) disease patients (58%) is lower than that reported for San Francisco black SS disease patients (87%) and similar to that reported for such New York patients (59%). There is, then, considerable heterogeneity among American black populations. Therefore, for the purposes of prenatal diagnosis, the frequency in the particular population at risk should be established. When the frequency of association of the 13-kb fragment and the beta S mutation is low, the linkage phase must also be established. When the linkage phase is known, the Hpa I pattern alone can exclude SS disease 54% of the time for Baltimore AS X AS couples.
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PMID:Population heterogeneity of the Hpa I restriction site associated with the beta globin gene: implications for prenatal diagnosis. 616 80

Twenty-six DNA samples from individuals either heterozygous or homozygous for beta thalassemia were analyzed by restriction endonuclease digestion, agarose gel electrophoresis, and Southern blot analysis to define DNA fragments containing portions or all of the beta globin gene. A total of twenty-seven genes affected by a beta thalassemia mutation and twenty-seven genes affected by a beta thalassemia mutation and twenty-two normal beta globin genes were examined in Italian, Greek, or Asian individuals. With all four restriction endonucleases used, the fragments generated from DNA of thalassemic individuals were identical to those found in DNA from normal. Thus, gross rearrangement or deletion within the genomic region containing the beta globin gene is not characteristic of mutations which cause a thalassemia. A third patient homozygous for pancellular hereditary persistence of fetal hemoglobin was shown to have complete deletion of the delta and beta globin genes.
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PMID:Analysis of globin gene structure in patients with beta thalassemia by restriction endonuclease mapping. 616 67

Restriction endonuclease mapping data are presented for the DNA of a young Indian homozygous patient (and his heterozygous parents) who were identified 10 years ago as having a G gamma-hereditary persistence of fetal haemoglobin (Sukumaran et al, 1972). However, the present results indicate a genetic lesion in these persons which is similar to that observed in another Indian with (A gamma delta beta)0-thalassaemia homozygosity (Amin et al, 1979) and is characterized by two relatively short deletions and an inversion involving the A gamma, delta and beta globin genes (Jones et al, 1981a). Some additional blot hybridization studies have provided further data confirming the deletion-inversion hypothesis.
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PMID:Restriction endonuclease gene mapping studies of an Indian (A gamma delta beta)zero-thalassaemia, previously identified as G gamma-HPFH. 620 82

Hereditary persistence of fetal hemoglobin (HPFH) is a genetically heterogeneous and clinically benign condition characterized by persistent expression of fetal hemoglobin (Hb F) into adulthood. In the G gamma beta + type, no major deletions in the globin gene cluster occur; adult heterozygotes produce approximately 20% Hb F, which results from overproduction of G gamma chains, with no apparent increase in production from the adjacent A gamma gene. We have recently described a point mutation 202 base pairs 5' to the cap site of the G gamma gene in an individual with G gamma beta + HPFH. This mutation abolishes a normal ApaI restriction endonuclease site, and thus can be detected by blotting of genomic DNA. We present here further data on the ApaI mutation: (1) It occurs in six of seven families with G gamma beta + HPFH. (2) In three families, detailed haplotype analysis using 11 polymorphic restriction sites in the beta globin cluster has been done. The two that carry the missing ApaI site are identical but the third, which has a normal ApaI pattern, differs from the other two in at least two sites, one of which is a new polymorphic Nco I site between the delta and beta globin genes. This suggests the possibility of a different HPFH mutation in the third family. (3) The haplotype of the G gamma beta + HPFH chromosome carrying the ApaI mutation is different from that of 108 beta A chromosomes of black individuals that have been tested. (4) The G gamma ApaI site is normal in 61 beta A and 109 beta S alleles from non-HPFH black individuals, including 22 who share the same haplotype for the intragenic G gamma, A gamma HindIII polymorphisms. These data add support to the possibility that the -202 mutation is actually causative of the G gamma beta + HPFH phenotype.
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PMID:Concordance of a point mutation 5' to the G gamma globin gene with G gamma beta +. Hereditary persistence of fetal hemoglobin in the black population. 620 55

The nucleotide sequence of the coding portion of human alpha globin mRNA has been determined by sequence analysis using human alpha globin cDNA cloned in bacterial plasmids. The sequence was obtained by a combination of direct sequence analysis of the cloned cDNA and analysis of cDNA obtained by primer extension, using short restriction endonuclease fragments of cloned alpha cDNA that were hybridized to human globin mRNA and elongated on the mRNA template by viral reverse transcriptase. The human alpha globin mRNA has an unexpectedly high G + C base composition (64.7%), similar to that observed for rabbit globin alpha mRNA, and displays a striking bias in the use of synonym codons for various amino acids. The bias in codon usage of human alpha globin mRNA is similar, with some exceptions, to that previously observed for rabbit alpha globin mRNA as well as for human and rabbit beta globin mRNAs. A detailed restriction endonuclease map of the human alpha globin cDNA is presented.
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PMID:Nucleotide sequence of the coding portion of human alpha globin messenger RNA. 624 94

beta globin gene fragments from a patient with homozygous beta+-thalassemia have been cloned and subjected to restriction endonuclease, nucleotide sequence, and in vitro trancription analyses. Restriction endonuclease mapping of the cloned gene fragments revealed no deletions or other rearrangements, and transcription of the thalassemic gene appeared to be normal in vitro. However, nucleotide sequence analysis of the beta+-thalassemic gene fragments permitted identification of a single base change in the body of the small intervening sequence. This nucleotide change creates a sequence much like that of the 3' splice site of the small intervening sequence. The presence of a potential anomalous splicing site as a result of this base change suggests a mechanism for defective posttranscriptional processing of beta globin mRNA precursor molecules in beta+-thalassemia.
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PMID:Base substitution in an intervening sequence of a beta+-thalassemic human globin gene. 626 77

A symptomless Iranian patient homozygous for beta thalassaemia has haematological changes similar to the beta thalassaemia trait. This remarkably mild phenotype is probably the result of coexistent alpha thalassaemia and increased gamma chain synthesis. Restriction endonuclease mapping analysis of the beta globin genes indicates that the patient is homozygous for a single nucleotide substitution at the 5' donor splice junction in the second intervening sequence of the beta globin gene. No other changes were observed in the non-alpha globin gene cluster. It seems unlikely that the augmented gamma chain synthesis in this patient is related to the molecular defect responsible for this beta o thalassaemia.
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PMID:The molecular basis for beta o thalassaemia intermedia in an Iranian individual. 628 64

Restriction endonuclease analysis has been performed on the alpha and beta globin gene clusters of 57 Cypriots homozygous for beta thalassaemia, 30 with the transfusion dependent form of the condition (thalassaemia major) and 27 who are less severely affected (thalassaemia intermedia). There was a significant difference in the incidence of alpha thalassaemia between the two groups: 14/27 of the patients with thalassaemia intermedia also had deletion forms of alpha thalassaemia, while only 4/30 of the patients with thalassaemia major were similarly affected. Thus in Cypriot patients who are homozygous for beta thalassaemia the co-inheritance of alpha thalassaemia is an important factor in determining the clinical course.
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PMID:Thalassaemia intermedia in Cyprus: the interaction of alpha and beta thalassaemia. 629 30

Genomic DNA from a hemoglobin (Hb) Lepore Boston (delta 87 Gln beta 116 His) homozygote of Southern Italian origin has been studied in order to map the fusion point between the delta and beta genes. An Ava II restriction endonuclease recognition sequence, located 12 base pairs (bp) downstream from the 5' end of the beta gene large intervening sequence, has been taken as marker of the beta-like portion of the fusion gene. This site was present even in the delta beta gene, allowing the localization of the crossover area to a 59-bp region extending from the first nucleotide of the Leu codon in position 88 to the 11th nucleotide of the large intervening sequence. The analysis of the DNA restriction polymorphisms in the gamma delta beta globin gene region provides evidence that a single mutational event originated the Lepore delta beta genes, at least in the Italian population.
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PMID:The delta beta crossover region in Lepore boston hemoglobinopathy is restricted to a 59 base pairs region around the 5' splice junction of the large globin gene intervening sequence. 630 43

The restriction endonuclease map of the alpha and beta globin genomic region of the new human erythroleukemia line, HEL, was compared with that of normal human DNA. The HEL line, which produces mainly fetal (G gamma and A gamma) but no adult (delta and beta) globin chains, was shown to have the same pattern of DNA fragments as that of normal human DNA. This suggests that the selective expression of the gamma globin genes observed in HEL cells is not due to a major deletion or rearrangement in the epsilon-G gamma-A gamma-delta-beta gene complex. Thus, the HEL line provides a model for studying the control of globin developmental switching in cells with structurally intact globin gene regions.
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PMID:Restriction endonuclease mapping of globin genomic regions of HEL (human erythroleukemia) line. 630 30


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