Ribosomal RNA gene amplification: A selective advantage in tissue culture

Roberts, CL; Brasch, J. M.; Tattersall, M. H. N.

doi:10.1016/0165-4608(87)90038-0

Cited by 15 publications

(5 citation statements)

References 14 publications

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“…It is thought that under certain conditions these genes may be amplified to form functional, identifiable NORs (Roberts et al, 1987;Takahashi et al, 1987). However, dis persal of these elements resembles transposition and may not be a separate event.…”

Section: Resultsmentioning

confidence: 99%

“…If NORs in bufonids are similarly controlled, there would be no expected advantage to having multiple NORs. However, amplified ribosomal genes have been shown to confer growth advantages to cells in culture (Roberts et al" 1987), and a translocation involving ribosomal genes has been shown to activate the c-abl oncogene (Takahaski et al, 1987). Transposed ribosomal genes could confer selective advantages to B. terrestris populations by activating dormant genes.…”

Section: Resultsmentioning

confidence: 99%

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Ribosomal RNA gene site polymorphism in <i>Bufo terrestris</i>

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Wiley²,

Little³

et al. 1991

Cytogenet Genome Res

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Individual specimens of Bufo terrestris were discovered that possessed ribosomal gene locations in addition to those normally found. Every specimen from an island population that was examined had extra sites, whereas fewer individuals from coastal mainland populations and none from inland populations had them. Although the extra ribosomal gene locations probably did not arise through gross structural chromosome rearrangements, their origin remains unclear.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ribosomal RNA gene site polymorphism in <i>Bufo terrestris</i>

Foote

Wiley²,

Little³

et al. 1991

Cytogenet Genome Res

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“…21 Second, argyrophilic staining of NORs is increased as a result of gene amplification. 17 Third, changes in AgNOR size and number are primarily the result of differences in the activation status of rDNA due to increased cell proliferation. 27 Egan et al 12 found significant differences in the size of AgNOR dots between high and low grade squamous intraepithelial lesions.…”

Section: Discussionmentioning

confidence: 99%

Significance of AgNOR Count in Differentiating Malignant Cells from Reactive Mesothelial Cells in Serous Effusions

Sujathan

Kannan²,

Pillai³

et al. 1996

Acta Cytologica

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“…Different cytogenetics explained differently the causes of increased NOR counts in malignancy. It may be due to increase in the chromosome number, increasing the chromosome arms containing NOR's (Schwarzacher et al, 1988), [4] gene amplification (Roberts et al, 1987), [15] but it is most significantly related to proliferation (Cairns et al 1989). [16] The AgNOR dots have been utilised for differentiating various histological types of tumours in biopsy specimens as in diagnosing malignancies of breast (Smith et al, 1988).…”

Section: Discussionmentioning

confidence: 99%

EVALUATION OF SEROUS EFFUSIONS USING AgNOR COUNT- A STUDY IN A TERTIARY CARE CENTRE OF SAHARANPUR

Sharma¹,

Sharma²,

Goyal³

2018

jemds

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BACKGROUND Abnormalities of nucleolar morphology are constant features of cancer cells. The importance of the nucleolus for the diagnosis of malignancy has been reconsidered after the observation that structural and morphological reorganisation is a consequence of the redistribution of the fibrillar components within the nucleolus. The nucleolar fibrillar components (fibrillar centre and associated dense fibrillar component) are the sites where ribosomal genes are located during interphase. They therefore represent the interphase counterpart of metaphase Nucleolar Organizer Regions (NOR's). The use of this parameter relative to interphase, NOR distribution has become of great importance after the finding that interphasic NOR's can be clearly visualised at the light microscopic level using a silver reaction, which stains the acidic proteins of the NOR's (AgNOR Proteins) on routinely prepared histo-and cytological samples. By means of this technique, silver-stained interphasic NOR's has been used for the diagnosis of malignancy of numerous neoplastic lesions. Cancer cells in fact have a greater number of silver-stained NOR's than the corresponding benign cells. The diagnosis of malignancy in cytologic preparations of pleural and peritoneal effusions is not always easily performed. Interest therefore has focussed on identifying reliable methods of supplementing conventional cytological methods to differentiate malignant cells from benign cells. Recently, AgNOR's (Silver Staining of Nucleolar Organizer Regions) have come to limelight. NOR's are being increasingly used in diagnosing a variety of tumours. Aims and Objectives: The objectives of the present study were 1. To identify reliable methods of supplementing conventional cytological methods to differentiate malignant cells from benign cells in serous effusions. 2. To study various serous effusions by conventional cytological methods. 3. To differentiate benign and malignant serous effusions on the basis of conventional cytological methods. 4. To study AgNOR count in differentiating malignant cells from benign cells in serous effusions and 5. To find out the utility of AgNOR counts in malignant vs benign cell differentiation in fluids. MATERIALS AND METHODS This is a descriptive study. We studied 65 cases of serous effusions over a period of one year from December 2016-December 2017. Samples for this study were collected from various outpatients and inpatients admitted in Medicine and Surgical wards. Staining and counting procedure. 1. Fluids collected were subjected to- Pap staining.  'AgNOR' staining. 2. Cytopathological evaluation of smears was done using Papanicolaou staining and further differentiation using AgNOR count. 3. The number of AgNOR's present in each nucleus were counted. Two hundred nuclei were taken into account. The mean AgNOR count of the specimen was then calculated. The AgNOR's were visualised using oil immersion objective and to avoid biased results, counts were done by two different observers. RESULTS A total of 43 cases (66.15%) of benig...

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Ribosomal RNA gene amplification: A selective advantage in tissue culture

Cited by 15 publications

References 14 publications

Ribosomal RNA gene site polymorphism in <i>Bufo terrestris</i>

Ribosomal RNA gene site polymorphism in <i>Bufo terrestris</i>

Significance of AgNOR Count in Differentiating Malignant Cells from Reactive Mesothelial Cells in Serous Effusions

EVALUATION OF SEROUS EFFUSIONS USING AgNOR COUNT- A STUDY IN A TERTIARY CARE CENTRE OF SAHARANPUR

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