AgNOR status in Down's syndrome infants and a plausible phenotype formation hypothesis

Demirtaş, Halil

doi:10.1016/j.micron.2009.02.014

Cited by 8 publications

(15 citation statements)

References 111 publications

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“…Furthermore, possible reduced expression of rRNA in brain, due to hypermethylation, was linked to risk of suicide [44]. Most recently, it has been suggested that increased rRNA due to trisomy of chromosome 21 contributes to Down's syndrome [45]. Thus variability in rRNA has relevance for several human health issues.…”

Section: Discussionmentioning

confidence: 99%

An Intergenic Non-Coding rRNA Correlated with Expression of the rRNA and Frequency of an rRNA Single Nucleotide Polymorphism in Lung Cancer Cells

Shiao

Lupascu

et al. 2009

PLoS ONE

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BackgroundRibosomal RNA (rRNA) is a central regulator of cell growth and may control cancer development. A cis noncoding rRNA (nc-rRNA) upstream from the 45S rRNA transcription start site has recently been implicated in control of rRNA transcription in mouse fibroblasts. We investigated whether a similar nc-rRNA might be expressed in human cancer epithelial cells, and related to any genomic characteristics.Methodology/Principal FindingsUsing quantitative rRNA measurement, we demonstrated that a nc-rRNA is transcribed in human lung epithelial and lung cancer cells, starting from approximately −1000 nucleotides upstream of the rRNA transcription start site (+1) and extending at least to +203. This nc-rRNA was significantly more abundant in the majority of lung cancer cell lines, relative to a nontransformed lung epithelial cell line. Its abundance correlated negatively with total 45S rRNA in 12 of 13 cell lines (P = 0.014). During sequence analysis from −388 to +306, we observed diverse, frequent intercopy single nucleotide polymorphisms (SNPs) in rRNA, with a frequency greater than predicted by chance at 12 sites. A SNP at +139 (U/C) in the 5′ leader sequence varied among the cell lines and correlated negatively with level of the nc-rRNA (P = 0.014). Modelling of the secondary structure of the rRNA 5′-leader sequence indicated a small increase in structural stability due to the +139 U/C SNP and a minor shift in local configuration occurrences.Conclusions/SignificanceThe results demonstrate occurrence of a sense nc-rRNA in human lung epithelial and cancer cells, and imply a role in regulation of the rRNA gene, which may be affected by a +139 SNP in the 5′ leader sequence of the primary rRNA transcript.

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Section: Discussionmentioning

confidence: 99%

An Intergenic Non-Coding rRNA Correlated with Expression of the rRNA and Frequency of an rRNA Single Nucleotide Polymorphism in Lung Cancer Cells

Shiao

Lupascu

et al. 2009

PLoS ONE

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“…Human diploid cells have about 400 copies of rRNA genes (Caburet et al, ). Therefore, extra chromosome 21 of individuals with DS contains approximately 40 extra copies of rRNA genes (Demirtas, ). The activities of the rRNA genes can be analysed particularly in both interphase and metaphase by using AgNOR or silver staining techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Some rDNA‐surrounded proteins are peculiarly argyrophilic and acidic nonhistone proteins and they are called as Argyrophilic Nucleolus Organizer Region (AgNOR) proteins (Rüschoff et al, ). In the AgNOR or silver staining technique, silver nitrate (AgNO 3 ) selectively stains these AgNOR proteins (Demirtas, ). By using AgNO 3 in suitable conditions, active (rRNA transcribing) NORs in interphase are stained by silver via the precipitation of metallic silver granules and the quantity of these silver granules is closely associated with NORs activity (Jimenez and Burgos, ; Ploton et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…By using AgNO 3 in suitable conditions, active (rRNA transcribing) NORs in interphase are stained by silver via the precipitation of metallic silver granules and the quantity of these silver granules is closely associated with NORs activity (Jimenez and Burgos, ; Ploton et al, ). Therefore, the staining intensity of AgNOR proteins by silver is directly correlated with the transcriptional activity of the ribosomal genes (Trerè, ) and it reveals the rDNA expression level in interphase cells (Demirtas, ; Hubbell, ; Pession et al, ; Roussel and Hernandez‐Verdun, ).…”

Section: Introductionmentioning

confidence: 99%

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Nuclear AgNOR protein enhancement in nucleoplasms of peripheral blood lymphocytes of babies/children with down syndrome

Imamoglu

Eröz

Canatan

et al. 2016

Microscopy Res & Technique

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Down syndrome (DS) is one of the most common chromosomal disorders. The factors contributing to the mental retardation together with other defects in this syndrome have not been fully explained. Individuals with DS have extra rRNA gene family since they carry an extra chromosome 21. The few reports available are on the relationship between the nucleolus organizer regions (NORs) and DS phenotype. The in vivo regulation of NORs expression on the extra chromosome 21 is not completely understood. Previous studies have shown that nucleoli of lymphocytes from infants (mostly neonates) with DS contain more in vivo and in vitro nucleolar AgNOR proteins when compared with healthy infants. The objective of this study is to compare the in vivo nuclear AgNOR protein level in nucleoplasms (also called as karyoplasm) of nonstimulated peripheral blood lymphocytes from babies/children with DS and healthy controls. Peripheral blood samples obtained from 20 babies/children with DS and 20 matched healthy controls were smeared on clean glass slides and then AgNOR staining was performed. The AgNOR protein level in nucleoplasms of lymphocytes from both groups was calculated using a computer program. Nearly 100 interphase nuclei per individual were analysed. Average nuclear AgNOR protein levels in nucleoplasms of lymphocytes from babies/children with DS were found to be significantly higher than those of the controls (P < 0.001). On the basis of our present results, we propose that the increase of nuclear AgNOR protein in in vivo conditions may contribute to the formation of DS phenotypes.

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“…*Address correspondence to this author at the Disciplina de Genética -Departamento de Morfologia e Genética, UNIFESP/EPM, Rua Botucatu, 740 -Vila Clementino, CEP: 04023-900, São Paulo, SP, Brasil; Tel: 55-11-5576 4260; Fax: 55-11-5576 4260; E-mail: macsmith.morf@epm.br Increase in the rDNA expression has been detected in lactents and infants with DS using this technique and Dermitas [9] proposed that this increase in ribosome biogenesis leading to disturbed protein synthesis may contribute to DS phenotype [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Ribosomal Genes Activity in Aged Down Syndrome Subjects

Goncalves¹,

Ávalos²,

Chen³

et al. 2011

TOGERIMJ

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Abstract:Objective: We aimed to investigate whether rRNA 28S/18S levels decrease with aging in Down Syndrome (DS) individuals and whether these decreased levels are tissue-specific. Methods:We investigated mature rRNA 28S/18S levels by Northern Blotting in blood cells from 21 younger and 21 older DS individuals in comparison to 42 age-sex-matched controls. We also investigated these levels in oral mucosa and in blood cells from the same DS individuals.Results: All DS subjects showed no clinical signs of dementia at the time of the study. We did not detect differences in rRNA 28S/18S levels among DS and control groups concerning either aging process or cell types.Conclusions: Aging process in DS individuals was not characterized by reduced rDNA transcriptional activity and did not indicate a preclinical marker of AD in older DS subjects.

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AgNOR status in Down's syndrome infants and a plausible phenotype formation hypothesis

Cited by 8 publications

References 111 publications

An Intergenic Non-Coding rRNA Correlated with Expression of the rRNA and Frequency of an rRNA Single Nucleotide Polymorphism in Lung Cancer Cells

An Intergenic Non-Coding rRNA Correlated with Expression of the rRNA and Frequency of an rRNA Single Nucleotide Polymorphism in Lung Cancer Cells

Nuclear AgNOR protein enhancement in nucleoplasms of peripheral blood lymphocytes of babies/children with down syndrome

Ribosomal Genes Activity in Aged Down Syndrome Subjects

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