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

---

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

Full-length, double-stranded globin DNA was synthesized in vitro starting from rabbit globin mRNA. Several restriction endonuclease cleavage sites with known recognition sequences were mapped on this DNA as a means of assessing the accuracy of in vitro synthesis. By comparing this map with the nucleotide sequences known or predicted from the amino acid sequences of alpha-and beta-chain rabbit hemoglobin, it was possible to show that the synthetic globin DNA is a faithful copy of beta-globin mRNA. Amplification of the synthetic globin DNA was achieved by inserting the molecule into the plasmid PMB9 using the poly(dA)-(dT) joining procedure, and transforming E. coli with the hybrid DNA. Transformants carrying beta-globin DNA were identified by colony hybridization using purified 125I-beta-mRNA probe. Comparison of the restriction maps of the synthetic and inserted globin DNAs showed that the entire synthetic globin DNA molecule was amplified without sequence rearrangements. Both the synthetic and the cloned DNA include the entire coding sequence of the beta-globin gene plus a substantial portion of the untranslated regions flanking the structural gene.
...
PMID:Amplification and characterization of a beta-globin gene synthesized in vitro. 6 Oct 66

Restriction endonuclease mapping of the human globin genes revealed a genetic variation in a Hpa I recognition site about 5000 nucleotides from the 3' end of the beta-globin structural gene. Instead of a normal 7.6-kilobase (kb) fragment which contains the beta-globin structural gene, 7.0-kb and 13.0-kb variants were detected. Both variants were found in people of African origin and were not detected in Asians or Caucasians. The 13.0-kb variant is frequently associated with the sickle hemoglobin mutation and may be useful for the prediction of the sickle cell gene in prenatal diagnosis. Polymorphism in a restriction enzyme site could be considered as a new class of genetic marker and may offer a new approach to linkage analysis and anthropological studies.
...
PMID:Polymorphism of DNA sequence adjacent to human beta-globin structural gene: relationship to sickle mutation. 28 13

Synthetic double-stranded DNAs (sDNAs) were prepared from sheep globin mRNA templates isolated from reticulocytes producing either hemoglobin B (HbB) (alpha 2 beta B2), HbC (alpha 2 beta C2), or HbF (alpha 2 gamma 2). These DNAs were inserted into the Eco RI site of plasmid pMB9 by the homopolymer tailing method and used to transform Escherichia coli X1776 to tetracycline resistance. Recombinant clones were identified by colony hybridization and further characterized by molecular hybridization and restriction endonuclease analysis. All plasmids analyzed thus far contained either beta- or gamma-globin DNA sequences. Moreover, sDNAs used for cloning yielded restriction endonuclease fragments consistent with the presence of predominantly beta- or gamma-sDNA, indicating that formation of double-stranded alpha-sDNA proceeds much less efficiently under our conditions than the formation of non-alpha-sDNAs. Three recombinant plasmids, pS beta B2, pS beta C69, and pS gamma 56, were selected for detailed study. These were shown to contain, respectively, beta B-, beta C-, and gamma-DNA sequences by molecular hybridization and by protection of the appropriate cDNAs from S1 nuclease digestion. Each contained all of the restriction endonuclease sites defined for the synthetic sDNAs and protected at least 90% of the sequence length of homologous cDNA. Restriction endonuclease maps of the beta B- and beta C-globin genes were identical at all 12 sites that were mapped, whereas four differences were identified in the gamma gene compared to the two others; three of these corresponded to differences in amino acid sequence of the globins. A method was developed to isolate the anti-mRNA strand of the insert for use as a specific molecular hybridization probe analogous to complementary DNA.
...
PMID:Hemoglobin switching in sheep. Synthesis, cloning, and characterization of DNA sequences coding for the beta B, beta C, and gamma-globin mRNAs. 37 94

The alpha-thalassemia syndromes are a group of inherited anemias, the clinical severity of which has been shown to increase with the number of alpha-globin structural genes deleted. Employing restriction endonuclease gene mapping, we defined the organization of the alpha-globin genes in cellular DNA from Chinese subjects with various alpha-thalassemia syndromes. The four alpha-globin genes of normals are at two loci located on a 23.0-kilobase pair (kb) Eco RI fragment. In deletion type hemoglobin-H disease the 5' alpha-globin locus is deleted and the single 3' alpha-globin locus is found on a 19.0-kb Eco RI fragment. In alpha-thalassemia-2 there are two alpha-globin genes on a 23.0-kb Eco RI fragment and one on a 19.0-kb fragment. In alpha-thalassemia-1 and the nondeletion type of hemoglobin-H disease the two alpha-globin genes are at two loci on one chromosome and none reside on the other chromosome.
...
PMID:Organization of the alpha-globin genes in the Chinese alpha-thalassemia syndromes. 44 45

We investigated the molecular basis of hemoglobin-H disease by hybridization and restriction endonuclease mapping of the DNA in the Mediterranean populations. Of the 12 patients studied from Cyprus and Sardinia, 8 had the typical deletion defect with a single remaining alpha-globin gene. The nondeletion type of alpha-thalassemia was found in 3, and a "dysfunctional" gene in one. We conclude that the predominant cause of alpha-thalassemia in these populations is gene deletion.
...
PMID:Molecular basis of hemoglobin-H disease in the Mediterranean population. 50 46

A new deletion of the beta-globin gene cluster has been characterized in two Italian brothers who are heterozygous carriers of a G gamma A gamma hereditary persistence of fetal hemoglobin (HPFH). Restriction endonuclease mapping and DNA sequencing of the region encompassing the breakpoint show that the deletion starts 3.2 kilobases (kb) upstream from the delta gene and ends within the enhancer region 3' to the beta-globin gene. Here the deletion removes one of the four binding sites for an erythroid specific transcriptional factor (NF-E1). The molecular comparison of the new deletion with others of similar size and location but associated with a delta beta-thalassemia phenotype suggests that the residual enhancer element, relocated near gamma genes, may increase the fetal hemoglobin (HbF) expression above the level observed in delta beta-thalassemia.
...
PMID:A new hereditary persistence of fetal hemoglobin deletion has the breakpoint within the 3' beta-globin gene enhancer. 168 88

We evaluated 61 patients with two screening tests for alpha-thalassemia traits on the basis of endonuclease gene mapping. Comparing these two methods--the osmotic fragility test of the red cell and modified hemoglobin H inclusion staining for the sensitivity--we found that the latter was much superior to the former with 100% sensitivity in detecting heterozygous alpha-1 thalassemia and it was also specific as a confirmatory test for thalassemia traits. Red cell indices are still the basic screening tool and can be used together with modified Hb H inclusion staining. The osmotic fragility test was not better than the red cell indices and was not confirmatory. Besides the MCV, RBC, and discrimination functions, we found that RBC distribution width-standard deviation (RDW-SD) was consistently low in heterozygous alpha-1 thalassemia but not in heterozygous alpha-2 thalassemia. None of the above tests was shown to be really helpful in screening in the latter situation. We conclude that the modified Hb H inclusion staining is superior to the osmotic fragility test in screening of alpha-1 thalassemia.
...
PMID:Comparison of two screening methods, modified Hb H preparation and the osmotic fragility test, for alpha-thalassemic traits on the basis of gene mapping. 172 96

Two human erythroleukemia cell lines, HEL and K562, express transglutaminase activity. The enzyme was identified as a tissue transglutaminase following chromatographic purification. All-trans-retinoic acid (10 microM) stimulated differentiation in HEL cells as judged by a 4-fold increase in hemoglobin content and a reduction in cell proliferation. The transglutaminase activity increased 9-fold. This increase in transglutaminase was the result of a pretranslational regulation of the gene as revealed by Northern blot analysis of mRNA. These changes were not a result of cell apoptosis, since parallel DNA degradation catalyzed by a Ca2(+)-dependent endonuclease could not be demonstrated. The K562 cells, in contrast, showed no transglutaminase induction following exposure to retinoic acid and displayed no changes in maturation markers or cell growth.
...
PMID:Differential expression of transglutaminase in human erythroleukemia cells in response to retinoic acid. 197 50

We have identified and molecularly characterized a novel deletion in the beta-globin gene cluster that increases fetal hemoglobin (HbF) synthesis in a 24-year-old Laotian man who is heterozygous for this mutation. The patient is asymptomatic with a mild anemia, hypochromia, and microcytosis (Ht = 39%, MCH = 22.8 pg, MCV = 71 fl), normal levels of HbA2 (3.0%) and 11.5% HbF (G gamma A gamma ratio 60 to 40), with heterocellular distribution (52% F cells). Extensive restriction endonuclease mapping defined the 5' breakpoint within the IVS II of the delta-globin gene, between positions 775 to 781 very similar to the 5' breakpoint of the Sicilian delta beta-thalassemia. However, the 3' breakpoint was localized between two Pst I sites 4.7 kb 3' of the beta-globin gene, thus ending about 0.7 kb upstream from the 3' breakpoint of the Sicilian delta beta-thalassemia. This results in a 12.5 kb deletion of DNA. It is of interest that the 5' breakpoint of the deletion residues within an AT-rich region which has been proposed as a specific recognition signal for recombination events, while the 3' breakpoint lies within a cluster of L1 repetitive sequences (formerly known as Kpn I family repeats). The presence of the 3' breakpoints of several other deletions within this region of L1 repeats also suggests that such sequences might serve as hot spots for recombination and eventually lead to thalassemia deletions. The similarity of the 5' and 3' breakpoints of these delta beta-thalassemias underscores the putative regulatory role of the deleted and juxtaposed sequences on the expression of the gamma-globin genes in adult life.
...
PMID:Laotian (delta beta) (0)-thalassemia: molecular characterization of a novel deletion associated with increased production of fetal hemoglobin. 245 54

Patients with sickle cell anemia vary in the hematologic and clinical features of their disease, in part because of variability in the presence of linked and unlinked genes that modify the expression of the disease. The hemoglobin S gene is strongly linked to three different haplotypes of polymorphic endonuclease-restriction sites of the beta-like gene cluster (genes in the vicinity of the beta-globin gene)--one prevalent in Atlantic West Africa, another in central West Africa, and yet another in Bantu-speaking Africa (equatorial, East, and southern Africa). We have studied the differences in the hematologic characteristics of patients with sickle cell anemia from the first two geographical areas. We find that the Senegalese (Atlantic West Africa) patients have higher levels of hemoglobin F, a preponderance of G gamma chains in hemoglobin F, a lower proportion of very dense red cells, and a lower percentage of irreversibly sickled cells than those from Benin (central West Africa). We interpret these data to mean that the gamma-chain composition and the hemoglobin F level are haplotype linked and that the decrease in the percentage of dense cells and irreversibly sickled cells is secondary to the elevation in the hemoglobin F level. Patients with sickle cell anemia in the New World probably correspond to various combinations of these types, in addition to the still hematologically undefined haplotype associated with sickle cell anemia in the Bantu-speaking areas of Africa.
...
PMID:Hematologically and genetically distinct forms of sickle cell anemia in Africa. The Senegal type and the Benin type. 257 36


1 2 3 4 5 Next >>

---