Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autoimmune serum from a patient with scleroderma was shown by indirect immunofluorescence to label nucleoli in a variety of cells tested including: rat kangaroo PtK2, Xenopus A6, 3T3, HeLa, and human peripheral blood lymphocytes. Immunoblot analysis of nucleolar proteins with the scleroderma antibody resulted in the labeling of a single protein band of 34 kD molecular weight with a pI of 8.5. Electron microscopic immunocytochemistry demonstrated that the protein recognized by the scleroderma antiserum was localized exclusively in the fibrillar region of the nucleolus which included both dense fibrillar and fibrillar center regions. Therefore, we have named this protein "fibrillarin". Fibrillarin was found on putative chromosomal nucleolar organizer regions (NORs) in metaphase and anaphase, and during telophase fibrillarin was found to be an early marker for the site of formation of the newly forming nucleolus. Double label indirect immunofluorescence and immunoelectron microscopy on normal, actinomycin D-segregated, and DRB-treated nucleoli showed that fibrillarin and nucleolar protein B23 were predominantly localized to the fibrillar and granular regions of the nucleolus, respectively. RNase A and DNase I digestion of cells in situ demonstrated that fibrillarin was partially removed by RNase and completely removed by DNase. These results suggest that fibrillarin is a widely occurring basic nonhistone nucleolar protein whose location and nuclease sensitivity may indicate some structural and/or functional role in the rDNA-containing dense fibrillar and fibrillar center regions of the nucleolus.
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PMID:Fibrillarin: a new protein of the nucleolus identified by autoimmune sera. 293 2

The induction and distribution of chromosomal transcripts in the polytene chromosomes of D. melanogaster and D. hydei has been investigated by indirect immunofluorescence using an antiserum directed against DNA/RNA hybrids. The fluorescence was intense and occurred in most of the chromosomal subdivisions when the chromosomes were exposed to denaturing conditions and then allowed to reanneal. The extent of hybrid formation depended both on the extent of DNA denaturation and on the maintenance of RNA integrity. Fluorescence was absent from chromosomes treated with pancreatic RNase before denaturation. The velocity of the chromosomal DNA/RNA hybridization reaction and the effects of the initiation inhibitor of RNA synthesis, DRB, suggest that in order to hybridize the RNA has to be located in its transcriptional compartment. Even though overall patterns of fluorescence seem to be similar during a developmental stage, variations were observed, particularly some correlated with puff induction after ecdysone stimulation.
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PMID:In situ immunofluorescent visualization of chromosomal transcripts in polytene chromosomes. 618 43

DRB genes encode proteins which play an important role in the immune response, and variation in their expression levels may be of functional immunological significance. To date, HLA class II gene promoter polymorphism has been analyzed almost exclusively in Epstein-Barr virus (EBV)-transformed B-cell lines. While previous studies have established important paradigms with regard to the mechanisms in DRB gene expression, the role of DRB4 promoter polymorphism in the variation of DRB4 expression levels, if any, is still unclear. We analyzed the effects of a previously described polymorphism in the promoter and 5' untranslated region of the DRB4 locus in peripheral blood mononuclear cells (PBMCs) from nine healthy DR7 individuals using the RNase protection assay. The RNase protection analyses showed that the location of transcription initiation is not affected. The DRB4 alleles show a threefold difference in pre-mRNA and a corresponding fivefold difference in mRNA levels in PBMCs. These data show that the DRB4 promoter polymorphism is associated with differential gene expression of this locus. The difference in pre-mRNA levels is directly affected by this DRB4 promoter polymorphism. The additional difference in mRNA levels is the result of post-transcriptional regulation. Therefore, the DRB4 promoter polymorphism may explain the previously observed variation in HLA class II DRB4 gene expression levels among different healthy DR7 individuals.
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PMID:DRB4 promoter polymorphism in DR7 individuals: correlation with DRB4 pre-mRNA and mRNA levels. 908 94