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)

Restriction endonuclease fragment length variations (RFLVs) were detected by using a rat cDNA probe for the bilirubin UDP-glucuronosyltransferase (UDPGT) gene between two mouse strains, 129/Sv and MOL-MIT. RFLVs of the gene were found by EcoRI and PvuII digestions. From linkage analyses of the three-point cross test using Elo and En-1 as marker genes, the bilirubin UDPGT gene was mapped at position 37 on chromosome 1. Bilirubin and phenol UDPGTs have been suggested to be expressed by a single gene by alternative splicing in human and rat. The mouse bilirubin UDPGT gene was named Gnt-1.
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PMID:Mapping of the mouse bilirubin UDP-glucuronosyltransferase gene (Gnt-1) to chromosome 1 by restriction fragment length variations. 135 70

Hepatic bilirubin excretion requires UDP-glucuronosyltransferase-mediated glucuronidation. Patients with type I Crigler-Najjar syndrome and mutant rats (Gunn strain) inherit deficiency of UDP-glucuronyltransferase activity toward bilirubin as an autosomal recessive trait and, as a result, exhibit marked nonhemolytic unconjugated hyperbilirubinemia throughout postnatal life. Heterozygous carriers of the trait have normal serum bilirubin levels. Because of placental excretion of unconjugated bilirubin, type 1 Crigler-Najjar syndrome patients and Gunn rats are not jaundiced in utero, making prenatal diagnosis difficult. Here we report a diagnostic method in Gunn rats based on genomic DNA analysis for prenatal recognition of deficiency of UDP-glucuronyltransferase activity toward bilirubin in Gunn rats and identification of heterozygous carriers. We and others have shown that two distinct messenger RNA species (UDP-glucuronyltransferase activity toward bilirubin and the 3-methylcholanthrene-inducible phenol-UDP-glucuronyltransferase messenger RNA) in Gunn rat liver contain identical deletions of a single guanosine residue in their common 3' regions. Loss of the restriction site for the endonuclease BstNI, which results from this deletion, was used as the basis for a diagnostic test. Female heterozygous Gunn rats were mated with male homozygous Gunn rats. Genomic DNA was extracted from the chorionic aspect of placenta of 17-day fetuses or from leukocytes from normal rats, obligate heterozygotes and homozygous Gunn rats. The DNA was sequentially digested with the restriction enzymes EcoRI and BstNI and subjected to Southern-blot analysis with a double-stranded DNA probe for the common region of UDP-glucuronyltransferase activity toward bilirubin and the 3-methylcholanthrene-inducible UDP-glucuronyltransferase messenger RNAs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prenatal diagnosis of bilirubin-UDP-glucuronosyltransferase deficiency in rats by genomic DNA analysis. 138 2

UDP-glucuronosyltransferase (transferase) clones were isolated from a cDNA bank constructed in pBR322 using transferase-enriched mRNA from the livers of phenobarbital-treated rats. The enrichment of mRNA was accomplished by polysome immunoadsorption with antibody to purified mouse liver transferase. This antibody was shown to bind specifically to rat transferase by Ouchterlony double diffusion analysis, immunoadsorption of glucuronidating activities, and selective inhibition of the immunoadsorption of in vitro synthesized enzyme by purified rat liver transferase. The isolated clones were verified to contain DNA complementary to transferase mRNA by hybrid translation-selection. Three classes of transferase cDNAs were characterized by restriction endonuclease mapping, and the largest insert-containing clone of each class was designated pUDPGTr-1, pUDPGTr-2, and pUDPGTr-3. Their insert sizes were approximately 2,400, 2,000, and 2,000 bp, respectively. All three cDNAs hybridized with a 2,300 +/- 150 bp mRNA, and each selected the translation of a 52,000-dalton polypeptide. Immunoadsorption of the 35S-labeled translation product could be competitively inhibited in each case by the addition of purified rat liver transferase. pUDPGTr-1 and pUDPGTr-3 inserts shared extensive sequence homology. This was demonstrated by Southern blot analysis using purified inserts and electron microscopic heteroduplex analysis. Southern blot analysis revealed that these cDNAs hybridized to overlapping genomic fragments. pUDPGTr-2 shared less sequence homology with the other two classes of cDNAs, based on the above criteria. In addition, mRNA corresponding to pUDPGTr-2 was elevated 5-fold by phenobarbital treatment, whereas the other mRNAs levels were unaffected. These studies demonstrate that in rat liver there are a minimum of three distinct transferase mRNAs, two of which may be associated with a common gene or gene family.
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PMID:Cloning and characterization of DNA complementary to rat liver UDP-glucuronosyltransferase mRNA. 620 73

The hyperbilirubinemic Gunn rat lacks hepatic UDP-glucuronosyltransferase (UDPGT) activity toward bilirubin and has been used as an animal model for human Crigler-Najjar syndrome type I. Rat liver bilirubin UDPGT cDNA was isolated. The cDNA shared an identical 913-bp sequence (corresponding to the C-terminal 247 amino acid residues) with that for phenol UDPGT whose activity was also deficient in the Gunn rat. The bilirubin UDPGT gene was mapped at the position of 37 on mouse chromosome 1 by analyzing restriction endonuclease fragment length variations using the rat bilirubin UDPGT cDNA as a probe. The genetic defect of bilirubin UDPGT in the mutant rat was proved to be a -1 frameshift mutation. The mutation was found not only to be located in the region where the cDNA for bilirubin UDPGT shared the identical sequence with that for phenol UDPGT but also to occur in the same position in the two cDNAs from the mutant.
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PMID:[Genetic defect of the hyperbilirubinemic Gunn rat, a model for Crigler-Najjar syndrome type I]. 809 54

An important consideration in application of hepatocyte transplantation is whether the number of engrafted hepatocytes is sufficient to achieve the desired effect. Here we have evaluated the proliferative potential of transplanted primary hepatocytes during regeneration of hepatic lobes. Two million hepatocytes isolated from congeneic normal Wistar-RHA rats were injected into the main portal vein of deficient, jaundiced Gunn rats. The right branch of the portal vein was ligated 24 hr before hepatocyte transplantation (group A) or transiently clamped during hepatocyte injection (group B) or 24 hr after hepatocyte injection (group C). In these groups, the three lobes supplied by the right branch of the portal vein rapidly atrophied and disappeared in 4 days, whereas the remaining lobes proliferated, as shown by size increase and 5-bromo-2-deoxy-uridine uptake. Two control groups received 2 million (group D) or 20 million hepatocytes (group E) without ligation. Hepatocyte engraftment occurred in all groups. The greatest hypobilirubinemic effect was observed in group A, in which serum bilirubin concentrations were reduced to 1.7+/-0.45 mg/dl from pretransplantation levels of 6.9+/-1.2 mg/dl. This effect was even greater than that observed after transplantation of 20 times more hepatocytes without ligation (group E). Specific endonuclease digestion of a polymerase chain reaction-amplified segment of the ugt1 gene from hepatic DNA showed that up to 25% of the DNA was of donor origin. This paralleled the hepatic bilirubin-UDP-glucuronosyltransferase activity, which was above 50% of normal. The results indicate that the transplanted hepatocytes proliferate preferentially within the regenerating lobes, replacing more than 20% of the liver mass with the progeny of the transplanted phenotypically normal hepatocytes.
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PMID:Massive repopulation of rat liver by transplantation of hepatocytes into specific lobes of the liver and ligation of portal vein branches to other lobes. 923 93

Crigler-Najjar syndrome type I is characterized by unconjugated hyperbilirubinemia resulting from an autosomal recessive inherited deficiency of hepatic UDP-glucuronosyltransferase (UGT) 1A1 activity. The enzyme is essential for glucuronidation and biliary excretion of bilirubin, and its absence can be fatal. The Gunn rat is an excellent animal model of this disease, exhibiting a single guanosine (G) base deletion within the UGT1A1 gene. The defect results in a frameshift and a premature stop codon, absence of enzyme activity, and hyperbilirubinemia. Here, we show permanent correction of the UGT1A1 genetic defect in Gunn rat liver with site-specific replacement of the absent G residue at nucleotide 1206 by using an RNA/DNA oligonucleotide designed to promote endogenous repair of genomic DNA. The chimeric oligonucleotide was either complexed with polyethylenimine or encapsulated in anionic liposomes, administered i.v., and targeted to the hepatocyte via the asialoglycoprotein receptor. G insertion was determined by PCR amplification, colony lift hybridizations, restriction endonuclease digestion, and DNA sequencing, and confirmed by genomic Southern blot analysis. DNA repair was specific, efficient, stable throughout the 6-month observation period, and associated with reduction of serum bilirubin levels. Our results indicate that correction of the UGT1A1 genetic lesion in the Gunn rat restores enzyme expression and bilirubin conjugating activity, with consequent improvement in the metabolic abnormality.
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PMID:Correction of the UDP-glucuronosyltransferase gene defect in the gunn rat model of crigler-najjar syndrome type I with a chimeric oligonucleotide. 1046 11