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)

Earlier, we reported that the 5' end of the normal beta-globin gene (beta) resides on a 1.14-kilobase DNA fragment, whereas the 5' end of the sickle cell gene (beta s) resides on a 1.34-kilobase fragment. In that blot hybridization analysis, we used genomic DNA digested with restricted endonuclease Mst II, and radioactive probes with short half-life. We demonstrate here that, if a biotinylated probe is used instead in a slightly modified procedure, sickle cell anemia can be quickly and directly detected if there is as much as 5 micrograms of total genomic DNA in the sample. This procedure obviates the special precautions necessary when radioactive materials are used.
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PMID:Use of biotinylated probes for detecting sickle cell anemia. 298 24

Gene probes can now be used to detect a variety of mutations that produce single-gene disorders. In present clinical practice, restriction endonuclease analysis is used for the prenatal diagnosis of sickle cell anemia, alpha-thalassemia, and beta-thalassemia. Direct detection of the mutation is possible in alpha-thalassemia, where a deletion has usually occurred, and in sickle cell anemia, where the mutation alters the recognition sequence of the restriction endonuclease, Mst II. Indirect detection of beta-thalassemia is based on using normal variations in DNA (DNA polymorphisms) to track normal and affected beta-globin genes in families. This latter kind of analysis is also useful in detecting the phenylalanine hydroxylase genes affected in phenylketonuria and will often be used in disorders where the mutations are unknown. In cases where the mutation is known, direct analysis by use of oligonucleotide probes is a new and important advance. An example of this type of gene detection in a family with classical hemophilia is presented. In addition, with chorion villus biopsy, detection of these inherited diseases is feasible by the 12th week of pregnancy.
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PMID:Gene probes: application to prenatal and postnatal diagnosis of genetic disease. 299 40

Restriction site polymorphisms are normal inherited variations in DNA that can be readily detected by restriction endonuclease analysis. Currently, 17 such polymorphisms are recognized within a 60 kb (kilobase) stretch of DNA which includes the beta-globin gene complex. Because of their proximity to the beta-globin gene, often these restriction site polymorphisms can be used to predict inheritance of beta-globin variants that produce disease. For example, restriction site polymorphisms can be used for prenatal diagnosis for the large majority of couples at risk of having a child with beta-thalassemia. When each member of such a couple is heterozygous at one or more of these 17 sites, family studies are usually successful in determining which forms of the polymorphism are co-inherited with the beta-thalassemia genes in that particular family. Subsequently, study of fetal DNA isolated from amniocytes obtained by midtrimester amniocentesis or from chorionic villi obtained by first trimester chorion biopsy will reveal which DNA polymorphisms that fetus has inherited. By deductive reasoning one can then predict which beta-globin genes it has co-inherited. Because of the general nature of these polymorphisms, which are related to the beta-globin gene and its variants only because of their proximity on chromosome 11, they are potentially useful in the prenatal diagnosis of any beta-chain hemoglobinopathy. Some hemoglobinopathies (including alpha-thalassemia, sickle cell anemia, and some cases of beta-thalassemia) can be detected directly by DNA analysis. In these cases in utero diagnosis does not need to rely on restriction site polymorphisms, which require preliminary family studies and are not applicable in all at risk pregnancies. Recently, genetic probes, which are necessary for detecting restriction site polymorphisms, have been isolated for sequences of several genes whose protein products are important in blood coagulation. These include probes for all three genes whose polypeptide products combine to form the fibrinogen molecule as well as probes for the prothrombin, Factor IX, Factor VIII, and antithrombin III genes. Defects in these genes are expected to be the causes of afibrinogenemia, prothrombin deficiency, hemophilia B, hemophilia A, and antithrombin III deficiency, respectively. From experience with other genes, it is expected that restriction site polymorphisms within and/or flanking these genes will be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Prenatal diagnosis of hemoglobinopathies by DNA analysis. 299 37

Two new methods were used to establish a rapid and highly sensitive prenatal diagnostic test for sickle cell anemia. The first involves the primer-mediated enzymatic amplification of specific beta-globin target sequences in genomic DNA, resulting in the exponential increase (220,000 times) of target DNA copies. In the second technique, the presence of the beta A and beta S alleles is determined by restriction endonuclease digestion of an end-labeled oligonucleotide probe hybridized in solution to the amplified beta-globin sequences. The beta-globin genotype can be determined in less than 1 day on samples containing significantly less than 1 microgram of genomic DNA.
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PMID:Enzymatic amplification of beta-globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. 299 80

Polymorphism for a Hpa I restriction endonuclease site associated with about 60% of beta S genes in American Blacks allows exact prenatal diagnosis of sickle cell anemia by amniocentesis in 36% of couples at risk. In three families in whom exact diagnosis by Hpa I sites was impossible, we found analysis for the presence of polymorphic HindIII sites in the G gamma and A gamma intervening sequences would allow an exact prenatal diagnosis of sickle cell status in all three. In one of these families, the presence of an A gamma HindIII site in amniocyte DNA confirmed the diagnosis (sickle cell trait) made by synthetic studies using fetal erythrocytes obtained at fetoscopy. Studies of other Black families and individuals provide evidence for linkage disequilibrium in the G gamma-A gamma-delta-beta gene complex involving the four sites, G gamma HindIII, A gamma HindIII, beta S, and Hpa I, which span 33 kilobases (kb). Ten of 14 chromosomes bearing a beta S gene in a 7.6-kb Hpa I fragment contained a G gamma but not an A gamma HindIII site, whereas 16 of 16 chromosomes bearing a beta S gene in a 13-kb Hpa I fragment lacked both the G gamma and A gamma HindIII sites. Two-thirds of beta A-bearing chromosomes lacked both G gamma and A gamma sites, whereas one-third contained either the G gamma or both G gamma and A gamma sites. These data demonstrate that combined analysis of both Hpa I and HindIII polymorphisms and verification of their linkage phase should increase the fraction of couples for whom amniocentesis can provide an exact diagnosis of sickle cell status from 36% to greater than 80%.
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PMID:Prenatal diagnosis of sickle cell anemia by restriction and endonuclease analysis: HindIII polymorphisms in gamma-globin genes extend test applicability. 624 72

Several reports have been published on the use of polymorphisms found in the human hemoglobin genes as a means for prenatal diagnosis of sickle cell anemia. The disadvantages of this approach reside in its limited application and the need for family analysis. Here we report that, by use of restriction endonuclease Dde I and diazobenzyloxymethyl-paper transfer procedures, a direct analysis can be made. Individuals with normal hemoglobin (AA) show two bands (175 and 201 base pairs) complementary to a 5'-specific beta-globin gene probe. Sickle cell trait individuals (AS) exhibit an additional band (376 base pairs). Individuals with sickle cell anemia (SS) show the band at 376 base pairs with a concomitant loss of the 175-base pair band. We interpret these changes in banding pattern to be the result of the elimination of a restriction site for Dde I in the altered codon associated with the sickle cell allele. Because an analysis can be performed on as little as 20 micrograms of cellular DNA, the application to prenatal diagnosis of sickle cell anemia should be possible.
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PMID:Direct identification of sickle cell anemia by blot hybridization. 627 89

We have reported the direct analysis of the allele for beta 2-globin by using restriction endonuclease Dde I coupled with blot-hybridization analysis. In that report we predicted that a major use of our analysis could be for the prenatal diagnosis of sickle cell anemia. Here we present such an analysis. In addition, this report also describes the use of a new enzyme Mst II, which also distinguish the beta s allele from the normal beta-globin allele. Blot-hybridization analysis with restriction endonuclease Mst II shows the 5' end of the normal beta-globin gene to reside on a fragment of approximately 1.14 kilobases, whereas the 5' end of the beta s-globin gene resides on a fragment of approximately 1.34 kilobases. Because the fragment sizes generated by Mst II are significantly larger than those generated by Dde I, one can easily perform a prenatal diagnosis for sickle cell by standard blot hybridizations onto nitrocellulose filters.
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PMID:Use of restriction endonucleases for mapping the allele for beta s-globin. 628 54

Enzymes which fragment DNA at specific sites have been used to prenatally detect sickle cell anemia, alpha-thalassemia, and beta-thalassemia from amniotic fluid aspirates. Within the last few years, the use of combined restriction endonuclease systems (EcoRI and HindIII) for the antenatal detection of sickle cell anemia was found to provide an exact diagnosis of sickle cell status in 80% of couples at risk. Similar systems have been developed for homozygous alpha- and beta-thalassemia. Clinical applications of this technique and future implications are discussed.
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PMID:The use of restriction endonucleases in the prenatal diagnosis of hemoglobinopathies. 628 41

The restriction endonuclease MstII cleaves the human beta-globin gene at the position corresponding to amino acids 5, 6, and 7. The beta S mutation at this position abolishes the recognition site. Hence, the two normal DNA fragments in this region, 1.15 and 0.2 kb in length, are replaced by a single 1.35-kb fragment in DNA from sickle cell anemia. We have set up an assay using these findings. The assay is extremely sensitive and can be applied to DNA directly harvested from 20 ml of amniotic fluid.
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PMID:A sensitive test for prenatal diagnosis of sickle cell anemia: direct analysis of amniocyte DNA with MstII. 630 79

We have used the restriction endonuclease mapping technique to analyse the globin genes in local cases of beta-thalassaemia major. No gross deletions or rearrangements of the beta-globin gene locus were detected. In one individual the point mutation within the beta-globin gene which gives rise to a beta(0)-thalassaemia allele was detected by use of a restriction enzyme which cuts the gene at this site. Analysis of restriction fragment length polymorphisms at the beta-globin locus showed that antenatal diagnosis of the disorder could be accomplished in an indigenous family with thalassaemia. The application of the gene-mapping technique to the diagnosis of sickle cell anaemia and alpha-thalassaemia is also discussed.
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PMID:Restriction endonuclease mapping of globin genes in beta-thalassaemia. 631 Aug 4


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