Interrelations between the maturation of a 100 kDa nucleolar protein and pre rRNA synthesis in CHO cells

Bouche, Gérard; Caizergues‐Ferrer, Michèle; Bugler, Béatrix; Amalríc, François

doi:10.1093/nar/12.7.3025

Cited by 124 publications

(76 citation statements)

References 28 publications

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“…In this report we studied the molecular mechanism by which nucleolin affects pol I transcription. We show, contrary to the model proposed several years ago (17,18), that nucleolin does not repress transcription through interaction with the nascent pre-rRNA transcript. Our results rather suggest an interaction of nucleolin with the RNA pol I machinery or the rDNA promoter sequence.…”

Section: Discussioncontrasting

confidence: 99%

“…This localization suggests that nucleolin could be involved in different aspects of ribosome biogenesis. Indeed, it has been proposed that nucleolin can regulate: (i) transcription of the rDNA genes (17)(18)(19)(20)(21), (ii) maturation of the pre-rRNA (22,23), and (iii) nucleocytoplasmic transport (24 -26).…”

mentioning

confidence: 99%

“…Because the N-terminal domain of nucleolin contains acidic regions that may interact with histones in chromatin and the central four RNA-binding domains interact with nascent prerRNA, it was proposed that nucleolin may form a bridge between the nascent transcript and chromatin, resulting in the blockage of transcription elongation (17,18). We used the Xenopus oocyte system to test this model.…”

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confidence: 99%

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Repression of RNA Polymerase I Transcription by Nucleolin Is Independent of the RNA Sequence That Is Transcribed

Roger¹,

Moisand²,

Amalríc³

et al. 2002

Journal of Biological Chemistry

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Nucleolin is one of the most abundant non-ribosomal proteins of the nucleolus. Several studies in vitro have shown that nucleolin is involved in several steps of ribosome biogenesis, including the regulation of rDNA transcription, rRNA processing, and ribosome assembly. However, the different steps of ribosome biogenesis are highly coordinated, and therefore it is not clear to what extent nucleolin is involved in each of these steps. It has been proposed that the interaction of nucleolin with the rDNA sequence and with nascent pre-rRNA leads to the blocking of RNA polymerase I (RNA pol I) transcription. To test this model and to get molecular insights into the role of nucleolin in RNA pol I transcription, we studied the function of nucleolin in Xenopus oocytes. We show that injection of a 2-4-fold excess of Xenopus or hamster nucleolin in stage VI Xenopus oocytes reduces the accumulation of 40 S pre-rRNA 3-fold, whereas transcription by RNA polymerase II and III is not affected. Direct analysis of rDNA transcription units by electron microscopy reveals that the number of polymerase complexes/ rDNA unit is drastically reduced in the presence of increased amounts of nucleolin and corresponds to the level of reduction of 40 S pre-rRNA. Transcription from DNA templates containing various combinations of RNA polymerase I or II promoters in fusion with rDNA or CAT sequences was analyzed in the presence of elevated amounts of nucleolin. It was shown that nucleolin leads to transcription repression from a minimal polymerase I promoter, independently of the nature of the RNA sequence that is transcribed. Therefore, we propose that nucleolin affects RNA pol I transcription by acting directly on the transcription machinery or on the rDNA promoter sequences and not, as previously thought, through interaction with the nascent pre-rRNA.The synthesis of functional ribosomes is a major task for the cell. Ribosomal gene transcription can account for as much as 40% of all cellular transcription and ribosomal RNA for about 80% of the RNA content of living cells (1). The different steps of ribosome biogenesis take place in a subcompartment of the nucleus called the nucleolus (2-4). The localization of the different steps of ribosome biogenesis in a single nuclear compartment probably allows an efficient coordination and regulation of ribosome assembly. The formation of mature ribosomes is one of the most complex assembly of ribonucleoparticles involving the interaction of four different RNAs and about 80 ribosomal proteins (5). In addition, several nucleolar non-ribosomal proteins are required for this process (6 -8). An ordered interaction of ribosomal and non-ribosomal proteins with pre-rRNA is probably required for the formation of functional ribosomes. The molecular details of this highly integrated process are still largely unknown.The non-ribosomal proteins fibrillarin and nucleolin as well as some ribosomal proteins have been detected on nascent prerRNA (9 -11) suggesting that they interact with the pre-rRNA during transcrip...

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confidence: 99%

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confidence: 99%

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Repression of RNA Polymerase I Transcription by Nucleolin Is Independent of the RNA Sequence That Is Transcribed

Roger¹,

Moisand²,

Amalríc³

et al. 2002

Journal of Biological Chemistry

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“…Nucleolin, through its aminoterminal region, can modulate the overall condensation state of rDNA chromatin (Egyhazi et al, 1988;Erard et al, 1988) and regulate transcription of ribosomal genes positively (Belenguer et al, 1990) or negatively (Bouche et al, 1984;Erard et al, 1990). In apparent contrast to our data, a recent article that analyzed the in situ localization of nucleolin in chromosome spreads did not observe signal above background over the rDNA strands (Ghisolfi-Nieto et al, 1996).…”

Section: Discussioncontrasting

confidence: 99%

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

McGrath

Smothers

Dadd

et al. 1997

MBoC

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“…We could show that the smaller 67-and 46-kDa bands derive from proteolysis of the 87-kDa protein (Supplemental Figure S4). This is similar to nucleolin, which in animals has aberrant migration on SDS-PAGE and is highly susceptible to proteolysis (Bouche et al, 1984).…”

Section: The Atnuc-l1 Gene Is Constitutively Expressed But Not Atnuc-l2mentioning

confidence: 73%

Characterization of AtNUC-L1 Reveals a Central Role of Nucleolin in Nucleolus Organization and Silencing of AtNUC-L2 Gene in Arabidopsis

Pontvianne

Matı́a

Douet

et al. 2007

MBoC

125

207

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Nucleolin is one of the most abundant protein in the nucleolus and is a multifunctional protein involved in different steps of ribosome biogenesis. In contrast to animals and yeast, the genome of the model plant Arabidopsis thaliana encodes two nucleolin-like proteins, AtNUC-L1 and AtNUC-L2. However, only the AtNUC-L1 gene is ubiquitously expressed in normal growth conditions. Disruption of this AtNUC-L1 gene leads to severe plant growth and development defects. AtNUC-L1 is localized in the nucleolus, mainly in the dense fibrillar component. Absence of this protein in Atnuc-L1 plants induces nucleolar disorganization, nucleolus organizer region decondensation, and affects the accumulation levels of pre-rRNA precursors. Remarkably, in Atnuc-L1 plants the AtNUC-L2 gene is activated, suggesting that AtNUC-L2 might rescue, at least partially, the loss of AtNUC-L1. This work is the first description of a higher eukaryotic organism with a disrupted nucleolin-like gene and defines a new role for nucleolin in nucleolus structure and rDNA chromatin organization.

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Interrelations between the maturation of a 100 kDa nucleolar protein and pre rRNA synthesis in CHO cells

Cited by 124 publications

References 28 publications

Repression of RNA Polymerase I Transcription by Nucleolin Is Independent of the RNA Sequence That Is Transcribed

Repression of RNA Polymerase I Transcription by Nucleolin Is Independent of the RNA Sequence That Is Transcribed

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

Characterization of AtNUC-L1 Reveals a Central Role of Nucleolin in Nucleolus Organization and Silencing of AtNUC-L2 Gene in Arabidopsis

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