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 three CD3 genes on human chromosome 11q23 encode proteins (gamma, delta and epsilon) which form part of the antigen receptor on T lymphocytes. All three genes are clustered within 50 kb and are activated approximately contemporaneously during the early stages of T cell ontogeny. In order to pinpoint potential regulatory sequences important for locus activation and tissue-specific gene expression, the chromatin structure of almost 90 kb of this region has been probed in five cell lines using the endonuclease pancreatic DNase I. A set of DNase I hypersensitive (HS) sites has been defined in T cell chromatin, five of which were strong and not found in non-T cells, with the exception of the erythroleukaemia cell line K562, in which three sites were weakly expressed, correlating with a low level of delta mRNA. The subset of five HS sites map close to the CD3 genes and lie in regions which contain elements of defined function: the gamma promoter; the delta promoter and its 3' enhancer; and the epsilon promoter and its 3' enhancer. Since no further major T cell-restricted HS sites lie within the 90kb of the CD3 locus analysed, these five regions may contain all the sequences important for CD3 gene expression.
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PMID:DNase I-defined chromatin configuration of the human CD3 gene cluster. 213 10

We report restriction endonuclease analysis of the gamma-delta-beta-globin gene region in a mother and child heterozygous for G gamma-beta +-hereditary persistence of fetal hemoglobin (HPFH). The affected chromosome in these persons directs the production of G gamma-chains and beta-chains but not A gamma-chains. DNA was digested with several restriction enzymes and was examined for gamma, delta, beta sequences by blot hybridization. Only normal digestion fragments were present. By sensitive methods, we were unable to detect a deletion in the entire gamma-delta-beta-globin gene region of the affected chromosome, indicating that in this family, G gamma-beta +-HPFH is not due to a large deletion.
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PMID:The gamma-delta-beta-globin gene region in G gamma-beta +-hereditary persistence of fetal hemoglobin. 617 63

Individuals heterozygous for the Greek (A gamma) variant of hereditary persistence of fetal haemoglobin (HPFH) synthesize Hb F whose gamma-globin chains are predominantly of the A gamma type. DNA obtained from Greek HPFH heterozygotes was used to test for abnormalities in the organization of non alpha-globin genes. In addition, gamma- and beta-globin expression was studied in BFUe cultures. Restriction endonuclease mapping showed that the G gamma, delta and beta genes in cis to the Greek HPFH determinant are intact. Overproduction of gamma-globin chains synthesis was observed in the BFUe cultures. A significant portion of the gamma chain synthesis was of the G gamma type, suggesting that the G gamma genes cis and trans to the HPFH chromosome are active in culture. DNA mapping data indicate that in contrast to G gamma A gamma HPFH and the G gamma (delta beta) thalassaemia, the Greek (A gamma) HPFH is not due to a large deletion in the non-alpha globin gene region. It is possible that the anomaly may result either from a small deletion or point mutation which influences non alpha-globin transcription. The in vitro synthesis data suggest that the low level of G gamma-globin chain synthesis in vivo is not the result of transcriptional inactivation of the G gamma gene, since this gene appears to be expressed in erythroid cell cultures. We speculate that the genetic lesion in Greek (A gamma) HPFH is in regulatory sequences which control the level of G gamma and A gamma expression during development.
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PMID:Greek (A gamma) variant of hereditary persistence of fetal haemoglobin: globin gene organization and studies of expression of fetal haemoglobins in clonal erythroid cultures. 617 32

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