scholarly journals The structure of the yeast ribosomal RNA genes. 3. Precise mapping of the 18 S and 25 S rRNA genes and structure of the adjacent regions

1981 ◽  
Vol 9 (4) ◽  
pp. 789-799 ◽  
Author(s):  
A.A. Bayev ◽  
O.I. Georgiev ◽  
A.A. Hadjiolov ◽  
N. Nikolaev ◽  
K.G. Skryabin ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Precise Mapping ◽  
Rna Genes

Basonuclin is associated with the ribosomal RNA genes on human keratinocyte mitotic chromosomes

1999 ◽  
Vol 112 (18) ◽  
pp. 3039-3047 ◽  
Author(s):  
H. Tseng ◽  
J.A. Biegel ◽  
R.S. Brown
Keyword(s):  
Ribosomal Rna ◽  
Zinc Fingers ◽  
Hair Follicles ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Control Element ◽  
Rrna Gene ◽  
Metaphase Chromosomes ◽  
Acrocentric Chromosomes ◽  
Rna Genes

Basonuclin is a zinc finger protein mainly expressed in keratinocytes of the basal layer of epidermis and the outer root sheath of hair follicles. It is also found in abundance in the germ cells of testis and ovary. In cultured keratinocytes, basonuclin is associated with chromatin in all phases of the cell cycle, including mitosis. By immunocytochemical methods, we demonstrate here that in mitosis basonuclin is associated with the short arms of the acrocentric chromosomes and with other loci on many metaphase chromosomes of human keratinocytes. Using the evolutionarily highly conserved N-terminal pair of zinc fingers in an electrophoresis mobility shift assay, we demonstrate that the DNA target sequences of basonuclin on the acrocentric chromosomes are likely to be within the promoter region of the 45S rRNA gene transcription unit. DNase I footprinting shows that basonuclin zinc fingers interact with the upstream control element of this promoter, which is necessary for the high level of transcription of the rRNA genes. This result suggests that basonuclin may be a tissue-specific transcription factor for the ribosomal RNA genes.

Detection of ribosomal RNA genes in soybean, Glycine max (L.) Merr., by in situ hybridization

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1091-1095 ◽  
Author(s):  
Halina Skorupska ◽  
Marc C. Albertsen ◽  
Kim D. Langholz ◽  
Reid G. Palmer
Keyword(s):  
In Situ Hybridization ◽  
Glycine Max ◽  
Ribosomal Rna ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Single Pair ◽  
Glycine Max L ◽  
Labeled Probe ◽  
Rna Genes

A biotinylated maize rRNA probe was hybridized to soybean nuclei. Hybridization was detected by using a streptavidin horseradish peroxidase biotin system. The procedure used enabled detection of heterologous complementary 18S and 25S rRNA coding genes in soybean. In diploid cultivars 'Hark' and 'Lincoln' a single pair of satellited chromosomes was present and two binding sites were detected at interphase. In plants trisomic for the satellited chromosome, three sites were observed, and in tetraploid nuclei, four sites were seen. The in situ hybridization results indicated that, for ribosomal RNA genes, Glycine max behaves as a diploid. We discuss the possibility of loss of a pair of satellited chromosomes in the evolution of soybean.Key words: biotin-labeled probe, rRNA genes, ploidy, Glycine max.

scholarly journals Exchange between the ribosomal RNA genes of X and Y chromosomes in Drosophila melanogaster males

1981 ◽  
Vol 38 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. H. Maddern
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Y Chromosomes ◽  
A Site ◽  
Rna Genes ◽  
Uniform Polarity

SUMMARYThe genes coding for the 18s and 28s ribosomal RNA (rRNA) are present on both the X and Y chromosomes of D. melanogaster at a site known as the bobbed locus. Exchange was observed in males between a normally orientated X and Y chromosome (Dp(1; 1) scv1 and BSY y31d) with a frequency of 0·079%. One-quarter (7 in 27) of these exchange products between two + chromosomes which both carried sufficient rRNA genes for a bb+ phenotype exhibited a bb phenotype. Evidence is presented that one-half, and possibly all, of the exchanges involved the repetitive bb genes. These results together with those reported by Palumbo, Caizzi & Ritossa (1973) imply that the repeated bb genes of either (or both) the X or Y chromosome are not arranged with uniform polarity and, further, that spermatogonial exchange between the X and Y chromosomes may be restricted to the bb loci.

Ribosomal RNA genes and the substructure of nucleolar organizing regions in Lilium

1984 ◽  
Vol 26 (2) ◽  
pp. 158-166 ◽  
Author(s):  
L. von Kalm ◽  
D. R. Smyth
Keyword(s):  
In Situ Hybridization ◽  
Ribosomal Rna ◽  
Relative Size ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Gene Number ◽  
Nucleolar Organizing Regions ◽  
Band Size ◽  
Rna Genes

We have examined the location and organization of nucleolar organizing regions (NORs) in the species Lilium henryi (with four NORs per diploid cell), L. longiflorum, and L. speciosum (each with six NORs), and the hybrids Lilium × 'Black Beauty' (five NORs) and Lilium × parkmannii (eight NORs). The relative number of genes in individual NORs was assayed by in situ hybridization using in vitro labelled ribosomal RNA (rRNA). An estimate of their relative transcriptional activity was obtained by scoring silver band size over the constriction. There was no clear correlation between gene number and activity at specific NORs. Rather, gene number correlated quite well with the relative size of heterochromatin usually found adjacent to NOR constrictions and stained by an acid-banding method. It is possible that many but a variable fraction of the rRNA genes in Lilium NORs are held inactive in nucleolar heterochromatin.Key words: ribosomal RNA genes, Lilium, nucleolus, in situ hybridization, heterochromatin, silver banding.

Variation of nuclear ribosomal RNA genes in Eragrostis tef (Zucc.) Trotter

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 815-821 ◽  
Author(s):  
Michael Pillay
Keyword(s):  
Ribosomal Rna ◽  
Restriction Site ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Eragrostis Tef ◽  
Length Variation ◽  
Rdna Repeat ◽  
Spacer Length ◽  
Repeat Units ◽  
Rna Genes

Variation in the ribosomal RNA genes (rDNA) was examined to assess the genetic variability among 314 plants representing 28 accessions of Eragrostis tef, an important food crop. A restriction site map was constructed for the species by localization of the BamHI, BglII, DraI, EcoRI, EcoRV, NdeI, SacI, SpeI, XbaI, and XhoI sites. A comparison of this map with those of other grasses showed conservation of sites, especially in the coding region. However, a unique EcoRI site combined with a BamHI site in the 18S region may be of diagnostic value for the species. A BamHI fragment that spans the intergenic spacer was used as an indicator of length variation of rDNA repeat units. rDNA repeat units in E. tef ranged in size from 8.4 to 11.07 kbp. Considerable size variation of rDNA repeats was present among accessions, between individual plants within some accessions, and within single plants. A total of 19 spacer length (sl) phenotypes was observed in 16 accessions in which 11–42 plants were analyzed. A single restriction site polymorphism was detected in PI442115 that was also distinguished by having a single sl variant. Variation in the rRNA genes is a useful indicator of genetic diversity in E. tef germplasm.Key words: Eragrostis tef, ribosomal DNA, restriction map, genetic variation.

scholarly journals A GENETIC LOCUS HAVING TRANS AND CONTIGUOUS CIS FUNCTIONS THAT CONTROL THE DISPROPORTIONATE REPLICATION OF RIBOSOMAL RNA GENES IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 88 (1) ◽  
pp. 67-79
Author(s):  
James D Procunier ◽  
Kenneth D Tartof
Keyword(s):  
Ribosomal Rna ◽  
Germ Line ◽  
Genetic Locus ◽  
Position Effect ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Position Effect Variegation ◽  
Compensatory Response ◽  
Cis Acting ◽  
Rna Genes

ABSTRACT The results of deficiency mapping experiments reveal the presence of a compensatory response (c r +) locus that is located distal to the cluster of ribosomal RNA (rRNA) genes and is responsible for disproportionately replicating these genes when cr+ locus is present in a single dose, as in X/O males or X / SC4 - Sc8 females. The cr+ locus is novel in that it exhibits both trans and contiguous cis acting properties in somatic cells. It acts in trans to detect the presence of its partner locus in the opposite homolog, and if that partner locus is absent, it acts in cis to drive the disproportionate replication of those rRNA genes (rDNA) that are contiguous with it. The ability of cr+ to function is independent of the number of ribosomal RNA genes present. Furthermore, it can be shown that the cr+ locus is not required for the magnification or reduction of germ line rDNA. Finally, the implications of cr+ for position-effect variegation and the apparent reversion of the abnormal oocyte (abo) phenotype are discussed.

scholarly journals Double-strand breaks in ribosomal RNA genes activate a distinct signaling and chromatin response to facilitate nucleolar restructuring and repair

2019 ◽  
Vol 47 (15) ◽  
pp. 8019-8035 ◽  
Author(s):  
Lea M Korsholm ◽  
Zita Gál ◽  
Lin Lin ◽  
Oliver Quevedo ◽  
Diana A Ahmad ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Ribosomal Rna ◽  
Double Strand Breaks ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Strand Breaks ◽  
Rrna Transcription ◽  
Damage Response ◽  
Rna Genes

Abstract The nucleolus is a nuclear sub-domain containing the most highly transcribed genes in the genome. Hundreds of human ribosomal RNA (rRNA) genes, located in the nucleolus, rely on constant maintenance. DNA double-strand breaks (DSBs) in rRNA genes activate the ATM kinase, repress rRNA transcription and induce nucleolar cap formation. Yet how ribosomal-DNA (rDNA) lesions are detected and processed remains elusive. Here, we use CRISPR/Cas9-mediated induction of DSBs and report a chromatin response unique to rDNA depending on ATM-phosphorylation of the nucleolar protein TCOF1 and recruitment of the MRE11–RAD50–NBS1 (MRN) complex via the NBS1-subunit. NBS1- and MRE11-depleted cells fail to suppress rRNA transcription and to translocate rDNA into nucleolar caps. Furthermore, the DNA damage response (DDR) kinase ATR operates downstream of the ATM-TCOF1-MRN interplay and is required to fully suppress rRNA transcription and complete DSB-induced nucleolar restructuring. Unexpectedly, we find that DSBs in rDNA neither activate checkpoint kinases CHK1/CHK2 nor halt cell-cycle progression, yet the nucleolar-DDR protects against genomic aberrations and cell death. Our data highlight the concept of a specialized nucleolar DNA damage response (n-DDR) with a distinct protein composition, spatial organization and checkpoint communication. The n-DDR maintains integrity of ribosomal RNA genes, with implications for cell physiology and disease.

scholarly journals Position effect suppression of ribosomal RNA genes in Drosophila melanogaster: non-autonomous in gynandromorphs?

1976 ◽  
Vol 28 (1) ◽  
pp. 89-91 ◽  
Author(s):  
Jagdeesh Pyati
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Position Effect ◽  
Preliminary Evidence ◽  
Genetic Evidence ◽  
Ribosomal Rna Genes ◽  
Rrna Genes ◽  
Rna Genes

SUMMARYBaker (1971) presented genetic evidence that the inviability of In(1)scL8/O and scS1/O males in Drosophila melanogaster is due to position effect suppression of ribosomal RNA cistrons. Although scL8/O and scS1/O males are inviable, scL8/scL8 and scS1/scS1 females are viable. We therefore asked the following question: Is scL8/O or scS1/O viable when part of a gynandromorph? In other words, is position effect suppression of rRNA genes autonomous or non-autonomous in gynandromorphs? In this paper preliminary evidence is presented which suggests that position effect suppression of rRNA cistrons is non-autonomous. The evidence is that scLS/ or scS1/O (male) parts of gynandromorphs are not only viable but normal in appearance.

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