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Hepatitis delta (delta) virus (HDV), a satellite virus of the hepatitis B virus (HBV), causes a severe form of viral hepatitis in humans. Here we present evidence based on electron microscopy and electrophoretic behaviour that HDV contains a single stranded circular RNA molecule. This is the first animal virus identified with a circular RNA genome. Circular(More)
We have studied splicing of precursors to the large ribosomal RNA and processing of the excised intron in yeast mitochondria using primer extension with reverse transcriptase and electron microscopy. Structural features of the following intermediates are described: first, a linear RNA carrying a 5'-terminal G that is not encoded in mitochondrial DNA;(More)
Thyroglobulin (Tg), the precursor of thyroid hormones, is a 660.000 Da dimeric glycoprotein synthesized exclusively in the thyroid gland. We have cloned the human thyroglobulin gene from cosmid and phage libraries and constructed a complete restriction map. The gene encodes an 8.7 kb mRNA, covers at least 300 kb DNA and contains at least 37 exons separated(More)
Excised group II introns in yeast mitochondria appear as covalently closed circles under the electron microscope. We show that these circular molecules are branched and resemble the lariats arising through splicing of nuclear pre-mRNAs in yeast and higher eukaryotes. One member of this intron class (aI5c in the gene for cytochrome c oxidase subunit I) is(More)
11S and 18S fractions of yeast mitochondrial RNAs, isolated by electrophoresis through agarose gels, have been found by electron microscopy to contain approximately 50% circular molecules. Circles in the 11S fraction have a contour length of 0.36 +/- 0.02 micron, which is approximately equal to the length of the majority of linear molecules also present.(More)
The mature apo Very Low Density Lipoprotein II (apo VLDLII) mRNA appears in chicken liver within a few hours after estrogen administration. Apart from this mRNA species, shorter RNA molecules hybridizing to apo VLDLII sequences have been detected in rooster liver upon estrogen stimulation. These molecules are present in the non-polyadenylated fraction of(More)
RNA containing the aI3 group I intron of the yeast mitochondrial gene encoding cytochrome oxidase subunit I shows self-splicing in vitro. The excised intron, comprising 1514 nucleotides, is partially split into an upstream portion, containing the intronic reading frame, and a downstream portion, containing the typical group I conserved sequence elements.(More)
Self-splicing of the precursor to large ribosomal RNA of yeast mitochondria leads not only to circles but also to lariats, structures that have not been observed before as products of self-splicing. Lariats were studied by electron microscopy after hybridization with an RNA complementary to the 3' half of the precursor. This leads to differentiation in at(More)
A series of overlapping recombinant clones, which cover the vitellogenin gene, has been isolated from a phage-lambda linked chicken gene library. The DNA of the overlapping clones spans 28 kb of contiguous DNA sequences in the chicken genome. Electron microscopic analysis of hybrids between vitellogenin mRNA and the genomic clones indicates that the chicken(More)
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