Results 191 to 200 of about 287,665 (235)
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Ribosomal DNA and the nucleolus at the heart of aging
Trends in Biochemical Sciences, 2022The rRNA genes [ribosomal DNA (rDNA)] are organized in a prominent nuclear compartment, the nucleolus. It is now well established that the nucleolus functions beyond ribosome biosynthesis, regulating several physiological cellular responses. The nucleoli constitute dynamic genomic/nuclear hubs and demonstrate unique inherent characteristics, rendering ...
Kasselimi, Eirini +3 more
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Circular ribosomal DNA and ribosomal DNA: replication in somatic amphibian cells
Chromosoma, 1975Pulse labelled rDNA from cultured somatic cells of Xenopus laevis was examined by electron microscope autoradiography. The pattern of replication closely resembles that of bulk chromosomal DNA and differs considerably from rDNA synthesis during amplification in the oocyte.
Jean-David Rochaix +2 more
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The Ribosomal DNA Plasmids of Entamoeba
Parasitology Today, 1998In most organisms, the nuclear ribosomal RNA (rRNA) genes are highly repetitive and arranged as tandem repeats on one or more chromosomes. In Entamoeba, however, these genes are located almost exclusively on extrachromosomal circular DNA molecules with no clear evidence so far of a chromosomal copy.
Sudha Bhattacharya +2 more
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Structure and organization of ribosomal DNA
Biochimie, 1991Three trends are seen in the organization of ribosomal DNA genes during evolution: 1) gradual separation and separability of the regulation of transcription of 5S and larger subunit rRNAs; 2) retention of a transcription unit containing both large and small rRNAs; and 3) clustering of genes for both 5S and 18S-28S rDNAs, with the possible association ...
D. Schlessinger, A.K. Srivastava
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Heterogeneity in cucumber ribosomal DNA
Theoretical and Applied Genetics, 1986Restriction and hybridization analysis of cucumber native ribosomal (r) DNA purified from actinomycin-D/CsCl gradients suggested that the repeat units were heterogeneous in both length and sequence. Several full length rDNA repeat units were cloned and five are described which account for all the EcoR I and Xba I fragments present in native DNA. One of
T. A. Kavanagh, J. N. Timmis
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Ribosomal DNA of Caenorhabditis elegans
Journal of Molecular Biology, 1981Abstract We have characterized the organization of the genes coding for 18 S, 5·8 S and 26 S ribosomal RNAs in the nematode Caenorhabditis elegans . These ribosomal genes, present in about 55 copies per haploid genome, alternate in a repeating tandem array.
David Hirsh, James G. Files
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Journal of Molecular Biology, 1980
Abstract We have analysed the ribosomal DNA of Calliphora erythrocephala, a Dipteran fly of the same sub-order as Drosophila melanogaster, through a series of rDNA † fragments cloned in a plasmid vector. We have mapped the sites for eight restriction enzymes within these plasmids, and positioned the regions coding for the 18 S and 28 S rRNAs within ...
Kathy Beckingham, Ray White
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Abstract We have analysed the ribosomal DNA of Calliphora erythrocephala, a Dipteran fly of the same sub-order as Drosophila melanogaster, through a series of rDNA † fragments cloned in a plasmid vector. We have mapped the sites for eight restriction enzymes within these plasmids, and positioned the regions coding for the 18 S and 28 S rRNAs within ...
Kathy Beckingham, Ray White
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Ribosomal DNA polymorphism in the genus Bifidobacterium
Research in Microbiology, 1996Ribosomal DNA polymorphism was studied in order to demonstrate intra- and interspecies differentiation of 42 Bifidobacterium strains. DNA from these strains was digested with the endonucleases BamHI, EcoRV, HindIII and PvuII and then analysed by Southern blotting. Ribosomal patterns using a part of an rRNA 23S gene as a probe clearly differentiated the
Mangin, I, Bourget, N, Decaris, B
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1988
The nucleolus organizer region (NOR) of maize chromosome 6 is now known to be the location of the 17/5.8/26S rDNA (hereafter termed 17/26S rDNA); this molecular information extends the NOR function to one of synthesizer as well as organizer. The extensive variation in ribosomal DNA (rDNA) multiplicity and the finding that much of the rDNA is in the NOR-
Irwin Rubenstein +3 more
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The nucleolus organizer region (NOR) of maize chromosome 6 is now known to be the location of the 17/5.8/26S rDNA (hereafter termed 17/26S rDNA); this molecular information extends the NOR function to one of synthesizer as well as organizer. The extensive variation in ribosomal DNA (rDNA) multiplicity and the finding that much of the rDNA is in the NOR-
Irwin Rubenstein +3 more
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Beyond ribosomal DNA: on towards the telomere
Chromosoma, 1997We have sequenced and analyzed 8.3 kb of sequence adjacent and distal to the human ribosomal DNA (rDNA); this distal sequence connects to the rDNA cluster just 4 kb upstream of the first promoter and is shared among the acrocentric chromosomes and, at least in part, it is also present in other primates.
Iris L. Gonzalez, James E. Sylvester
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