Immunolocalization of Human p14ARF to the Granular Component of the Interphase Nucleolus

Lindström, Mikael S.; Klangby, Ulf; Inoue, Rie; Pisa, Pavel; Wiman, Klas G.; Asker, Charlotte

doi:10.1006/excr.2000.4854

Cited by 77 publications

(76 citation statements)

References 45 publications

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“…In agreement with earlier studies, the presence of immunoreactive p14 ARF was indicated by granular or diffuse nuclear staining, with or without nucleolar accentuation (17,18); cytoplasmic staining was observed even in cells with homozygous deletions of the INK4a gene and may thus be nonspecific. In some normal cells, cell lines and tumors, the staining pattern was predominantly nucleolar, consistent with the recently described nucleolar sequestration of MDM2 by p14 ARF (7,19,20). The significance of the somewhat variable subcellular localization is unclear, but it does not seem to be related to fixation.…”

Section: Correlation Between Arf Status and P14 Arf Expressionsupporting

confidence: 84%

“…Our data are consistent with earlier findings of p14 ARF mRNA and protein expression in MDA-MB-468 breast cancer cells (20) and with absence of exon 1␤ promoter methylation in many colorectal cancer cell lines (8). T47D breast cancer cells were previously found to be p14 ARF negative by immunofluorescence but positive by RT-PCR, and U20S osteosarcoma cells were reported to be negative but inducible for p14 ARF (19). Both cell lines showed nuclear staining in our IHC assay, indicating good sensitivity.…”

Section: Correlation Between Arf Status and P14 Arf Expressionmentioning

confidence: 51%

“…Although we optimized the assay for only one of the five antibodies tested, monoclonal 14PO2 from NeoMarkers, which has been used before in immunofluorescence assays (19), it is quite possible that comparable results may be obtained with other anti-p14 ARF antibodies. In agreement with earlier studies, the presence of immunoreactive p14 ARF was indicated by granular or diffuse nuclear staining, with or without nucleolar accentuation (17,18); cytoplasmic staining was observed even in cells with homozygous deletions of the INK4a gene and may thus be nonspecific.…”

Section: Correlation Between Arf Status and P14 Arf Expressionmentioning

confidence: 99%

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utImmunohistochemical Detection of the Alternate INK4a-Encoded Tumor Suppressor Protein p14ARF in Archival Human Cancers and Cell Lines Using Commercial Antibodies: Correlation with p16INK4a Expression

2001

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The INK4a locus encodes two structurally unrelated tumor suppressor proteins, p16 INK4a and p14 ARF . Although the former is one of the most common targets for inactivation in human neoplasia, the frequency of p14 ARF abrogation is not established. We have developed an immunohistochemical assay that allows the evaluation of p14 ARF expression in formalin-fixed, paraffin-embedded tissues, using commercially available antibodies. p14 ARF positive cells showed nuclear/nucleolar staining, which was absent in all cell lines and tumors with homozygous deletions of the INK4a gene. The assay was applied to 34 paraffin-embedded cell buttons, 30 non-small cell lung cancers and 28 pancreatic carcinomas, and the staining results were correlated with p16 INK4a expression. Loss of p14 ARF expression was common but less frequent than down-regulation of p16 INK4a (53% versus 76% of all specimens). The p14 ARF and p16 INK4a expression pattern was concordant in 65 of 92 cases (71%). Significantly, 24 cases were p16 INK4a ؊/p14 ARF ؉, while the opposite staining pattern was observed in three cases, consistent with the notion that the two proteins have nonredundant functions. The immunohistochemical assay described here may facilitate studies on the prevalence and significance of aberrant p14 ARF expression in human tumors.

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Section: Correlation Between Arf Status and P14 Arf Expressionsupporting

confidence: 84%

Section: Correlation Between Arf Status and P14 Arf Expressionmentioning

confidence: 51%

Section: Correlation Between Arf Status and P14 Arf Expressionmentioning

confidence: 99%

See 1 more Smart Citation

utImmunohistochemical Detection of the Alternate INK4a-Encoded Tumor Suppressor Protein p14ARF in Archival Human Cancers and Cell Lines Using Commercial Antibodies: Correlation with p16INK4a Expression

2001

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“…However, this regulation on its own is clearly not sufficient to inhibit cell proliferation. In this context, p19 ARF and p14 ARF have been recently identified as inhibitors of ribosomal processing through their interaction with both B23/nucleophosmin and 5.8S (Lindstrom et al, 2000;Eymin et al, 2003;Sugimoto et al, 2003). B23 possesses an intrinsic endoribonuclease activity involved in the processing of the 32S rRNA into the mature 28S subunit (Savkur and Olson, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…More recently a role for Arf in the control of ribosome biogenesis has been suggested: p19 ARF delays rRNA processing in a mdm2 and p53-independent manner (Sugimoto et al, 2003) and associates in very high molecular weight complexes with NPM/B23, a protein involved in the maturation of preribosomal particles (Bertwistle et al, 2004). The human homologue p14 ARF has been shown to partially colocalize with NPM/B23 in the granular component of the nucleolus and to induce its degradation, resulting in the inhibition of rRNA levels and cell death induction (Lindstrom et al, 2000;Itahana et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Human tumor suppressor p14ARF negatively regulates rRNA transcription and inhibits UBF1 transcription factor phosphorylation

Ayrault¹,

Andrique²,

Fauvin³

et al. 2006

Oncogene

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The nucleolar Arf protein has been shown to regulate cell cycle through both p53-dependent and -independent pathways. In addition to the well-characterized Arf-mdm2-p53 pathway, several partners of Arf have recently been described that could participate in alternative regulation process. Among those is the nucleolar protein B23/NPM, involved in the sequential maturation of rRNA. p19 ARF can interact with B23/NPM in high molecular complexes and partially inhibit the cleavage of the 32S rRNA, whereas the human p14 ARF protein has been shown to participate in the degradation of NPM/B23 by the proteasome. These data led to define Arf as a negative regulator of ribosomal RNA maturation. Our recent finding that the human p14 ARF protein was able to specifically interact with the rRNA promoter in a p53-independent context, led us to analyse in vitro and in vivo the consequences of this interaction. Luciferase assay and pulse-chase experiments demonstrated that the rRNA transcription was strongly reduced upon p14 ARF overexpression. Investigations on potential interactions between p14 ARF and the transcription machinery proteins demonstrated that the upstream binding factor (UBF), required for the initiation of the transcriptional complex, was a new partner of the p14 ARF protein. We next examined the phosphorylation status of UBF as UBF phosphorylation is required to recruit on the promoter factors involved in the transcriptional complex. Upon p14 ARF overexpression, UBF was found hypophosphorylated, thus unable to efficiently recruit the transcription complex. Taken together, these data define a new p53-independent pathway that could regulate cell cycle through the negative control of rRNA transcription.

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p 14 ARF / p 19 ARF

Lindstr��m¹,

Asker²,

Wiman³

2002

Wiley Encyclopedia of Molecular Medicine

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Immunolocalization of Human p14ARF to the Granular Component of the Interphase Nucleolus

Cited by 77 publications

References 45 publications

utImmunohistochemical Detection of the Alternate INK4a-Encoded Tumor Suppressor Protein p14ARF in Archival Human Cancers and Cell Lines Using Commercial Antibodies: Correlation with p16INK4a Expression

utImmunohistochemical Detection of the Alternate INK4a-Encoded Tumor Suppressor Protein p14ARF in Archival Human Cancers and Cell Lines Using Commercial Antibodies: Correlation with p16INK4a Expression

Human tumor suppressor p14ARF negatively regulates rRNA transcription and inhibits UBF1 transcription factor phosphorylation

p 14 ARF / p 19 ARF

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