title: Non-canonical ribosomal DNA segments in the human genome, and nucleoli functioning.
abstract: Ribosomal DNA (rDNA) in the human genome is represented by tandem repeats of 43 kb nucleotide sequences that form nucleoli organizers (NORs) on each of five pairs of acrocentric chromosomes. RDNA-similar segments of different lengths are also present on (NOR)(-) chromosomes. Many of these segments contain nucleotide substitutions, supplementary microsatellite clusters, and extended deletions. Recently, it was shown that, in addition to ribosome biogenesis, nucleoli exhibit additional functions, such as cell-cycle regulation and response to stresses. In particular, several stress-inducible loci located in the ribosomal intergenic spacer (rIGS) produce stimuli-specific noncoding nucleolus RNAs. By mapping the 5'/3' ends of the rIGS segments scattered throughout (NOR)(-) chromosomes, we discovered that the bonds in the rIGS that were most often susceptible to disruption in the rIGS were adjacent to, or overlapped with stimuli-specific inducible loci. This suggests the interconnection of the two phenomena - nucleoli functioning and the scattering of rDNA-like sequences on (NOR)(-) chromosomes.
authors.affiliation: The Institute of Gene Biology, RAS, 34/5, Vavilov St., Moscow, Russian Federation. Electronic address: cuprum242@rambler.ru.
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Kupriyanova
authors.affiliation: The Institute of Gene Biology, RAS, 34/5, Vavilov St., Moscow, Russian Federation. Electronic address: neck5@rambler.ru.
authors.forename: Kirill K
authors.initials: KK
authors.lastname: Netchvolodov
authors.affiliation: The Institute of Gene Biology, RAS, 34/5, Vavilov St., Moscow, Russian Federation. Electronic address: nastushka_1992@mail.ru.
authors.forename: Anastasia A
authors.initials: AA
authors.lastname: Sadova
authors.affiliation: The Institute of Gene Biology, RAS, 34/5, Vavilov St., Moscow, Russian Federation. Electronic address: sunshine_im@mail.ru.
authors.forename: Marina D
authors.initials: MD
authors.lastname: Cherepanova
authors.affiliation: The Institute of Gene Biology, RAS, 34/5, Vavilov St., Moscow, Russian Federation. Electronic address: ryskov@mail.ru.
authors.forename: Alexei P
authors.initials: AP
authors.lastname: Ryskov
mesh_terms: D002466:Cell Nucleolus / Q000235:genetics / Q000502:physiology*; D002877:Chromosomes, Human / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics*; D005786:Gene Expression Regulation; D015894:Genome, Human; D006801:Humans; D009697:Nucleolus Organizer Region / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal
keywords: Human genome; ncRNA transcription; rDNA scattering; rIGS inducible loci