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)

A Moroccan woman was investigated because of a typical beta-thalassemia trait associated with a low-percentage (11%) hemoglobin (Hb) variant. The beta-thalassemia trait was manifested by a microcytosis, a high HbA2 (above 6%), and an increase of the alpha/beta biosynthetic ratio (1.31). The variant was identified to HbS by amino acid analysis of the abnormal peptide (beta T1) and by DNA mapping with Sau I (Mst II) restriction endonuclease. No additional amino acid substitution was recorded in the beta s-chain. The reduction of beta-globin synthesis occurred exclusively at the expense of the beta s-chain. These results are consistent with the existence of a beta s mutation and a beta +-thalassemia in cis.
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PMID:Association in cis of beta +-thalassemia and hemoglobin S. 367 4

Restriction endonuclease mapping defined a partial deletion of about 1.35 kb in the beta-globin gene of a black American patient with hemoglobin S-beta zero-thalassemia and in his uncle with a beta zero-thalassemia trait. The 5' endpoint of the deletion is about 600 bases upstream from the cap site, and the 3' endpoint lies within about 500 bases from the 5' splice junction of the second intervening sequence. The deletion is different from that of a previously reported Indian beta zero-thalassemia allele, where 0.6 kb is deleted at the 3' end of the beta-globin gene.
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PMID:Partial deletion of the 5' beta-globin gene region causes beta zero-thalassemia in members of an American black family. 608 38

Members of a Jewish family of Polish origin were found to have hypochromic, microcytic erythrocytes. By restriction endonuclease analysis of DNA, the propositus, a brother, and an aunt were found to have a single alpha-globin gene on each chromosome 16. Five family members have one chromosome bearing two alpha-genes (5' and 3') with a single alpha-gene on the homologous chromosome. Gene mapping indicated that the chromosome bearing a single alpha-gene arose via an unequal crossover between misaligned 5' and 3' alpha-genes and was introduced into the family from three separate sources. In addition, a Jewish man of Hungarian origin was found to have alpha-thalassemia trait with single alpha-genes on both chromosomes 16 and a survey of 25 Jewish subjects yielded one man of German origin with an alpha-gene deletion. Alpha-thalassemia should be considered in the differential diagnosis of disease in Jewish persons with microcytic, hypochromic erythrocytes.
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PMID:Alpha-thalassemia in Ashkenazi Jews. 630 47

In humans the alpha-globin genes are duplicated and closely linked. Whereas individuals heterozygous for most alpha-chain mutations possess approximately 25% abnormal hemoglobin, heterozygotes for the alpha-chain variant Hb G Philadelphia synthesize either 33% or 50% Hb G. Both variable gene dosage and interaction with alpha-thalassemia have been proposed to explain this observation. To differentiate between these models, we have performed restriction endonuclease mapping and hematological studies on individuals with Hb G from four families. In every case the alpha G locus was carried on an EcoRI or EcoRI + BamHI fragment approximately 4 kilobases shorter than that bearing the two linked alpha A loci of hematologically normal individuals. Bgl II digestion revealed that the alpha G gene is the only alpha locus on the affected chromosome. Erythrocyte indices and alpha/beta synthesis ratios indicated that the alpha G chromosome confers alpha-thalassemia. In addition to the alpha G gene, subjects who synthesized 33% Hb G possessed two alpha A genes on the homologous chromosome and exhibited the mild form of alpha-thalassemia trait ("silent carrier"). Subjects who synthesized 50% Hb G possessed a single alpha A gene trans to the alpha G locus and displayed the more pronounced form of alpha-thalassemia trait. One subject, who synthesized 100% alpha G chains and had Hb G-Hb H disease, was found to have a single nonfunctional alpha gene trans to the alpha G gene. Thus the proportion of Hb G synthesized by heterozygotes is determined by interaction with alpha-globin gene deletions cis and trans to the alpha G locus.
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PMID:Proportion of hemoglobin G Philadelphia (alpha 268 Asn leads to Lys beta 2) in heterozygotes is determined by alpha-globin gene deletions. 693 89

Utilizing restriction endonuclease mapping and molecular hybridization we have determined the number and arrangement of the alpha-globin genes in members of an American Black family in which alpha-thalassemia is present. In addition to chromosomes bearing 0, 1 or 2 alpha-genes, an unusual chromosome bearing 3 alpha-globin genes was detected in 3 family members. In 2 family members the 3 alpha-globin gene chromosome was present opposite a chromosome containing a single alpha-globin gene; these cases represent the first reports of the alpha alpha alpha/-alpha genotype. The presence of the stigmata of "mild" alpha-thalassemia trait in one of these subjects indicates that the 3 alpha-gene chromosome probably does not direct the synthesis of significantly more alpha-globin chains than does the 2 alpha-gene chromosome.
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PMID:Interaction of chromosomes bearing 1, 2 or 3 alpha-globin genes in an American black family with alpha-thalassemia. 709 14

Four parents of three unrelated families who are obligatory beta-thalassemia heterozygotes and two parents with Hb Knossos are presented. In these subjects, although the red blood cell counts and red cell indices were compatible with beta-thalassemia trait, the Hb A2 values were between 1.9-2.9% of the total hemoglobin. Examination of the delta-globin gene by Southern blot, restriction endonuclease analysis, and by direct sequencing of amplified DNA revealed the presence of the (delta0) -7.2 kb Corfu type deletion, the (delta+) codon 27 (G-->T) and (delta0) IVS-I-2 (T-->C) mutations in trans or in cis with a severe beta-thalassemia allele, and the (delta0) codon 59 (-A) deletion in cis with the betaKnossos allele.
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PMID:Molecular analysis of turkish beta-thalassemia heterozygotes with normal Hb A2 levels. 1097 39