Localization and phosphorylation of nuclear, nucleolar and extranucleolar non-histone proteins of Novikoff hepatoma ascites cells

Olson, Matthew S.; Ezrailson, Edward G.; Guetzow, Karl; Busch, Harris

doi:10.1016/s0022-2836(75)80062-3

Cited by 45 publications

(31 citation statements)

References 27 publications

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“…The core structure, which comprises acidic and glycinerich domains as well as four RNA-binding domains (RBDs) (43), is extensively modified by targeted proteolysis (14,24), phosphorylation (13,54,59,60,67), ADP ribosylation (44), and methylation (46), resulting in combinatorial structural complexity that may form the basis for its observed functional heterogeneity. The four centrally positioned RBDs of nucleolin mediate its interaction with RNA both in the nucleus (32,33) and in the cytoplasm (15,56,58,69,71,72,85,86).…”

Section: Discussionmentioning

confidence: 99%

A Nucleolin-Binding 3′ Untranslated Region Element Stabilizes β-Globin mRNA In Vivo

Jiang¹,

Xu²,

Russell

2006

Molecular and Cellular Biology

107

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The normal expression of human ␤ globin is critically dependent upon the constitutively high stability of its encoding mRNA. Unlike with ␣-globin mRNA, the specific cis-acting determinants and trans-acting factors that participate in stabilizing ␤-globin mRNA are poorly described. The current work uses a linker-scanning strategy to identify a previously unknown determinant of mRNA stability within the ␤-globin 3 untranslated region (3UTR). The new determinant is positioned on an mRNA half-stem opposite a pyrimidine-rich sequence targeted by ␣CP/hnRNP-E, a factor that plays a critical role in stabilizing human ␣-globin mRNA. Mutations within the new determinant destabilize ␤-globin mRNA in intact cells while also ablating its 3UTR-specific interaction with the polyfunctional RNA-binding factor nucleolin. We speculate that 3UTR-bound nucleolin enhances mRNA stability by optimizing ␣CP access to its functional binding site. This model is favored by in vitro evidence that ␣CP binding is enhanced both by cis-acting stem-destabilizing mutations and by the trans-acting effects of supplemental nucleolin. These studies suggest a mechanism for ␤-globin mRNA stability that is related to, but distinct from, the mechanism that stabilizes human ␣-globin mRNA.Erythroid cells accumulate hemoglobin through a process that is critically dependent upon the high stabilities of mRNAs that encode their constituent ␣-and ␤-globin subunits (10, 64). In vivo analyses estimate a half-life for human ␣-globin mRNA of between 24 and 60 h (47,62,63,74), while similar studies with cultured NIH 3T3 and murine erythroleukemia (MEL) cells (2, 36, 42), primary mouse hematopoietic cells (4), and human erythroid progenitors (62, 63) suggest a half-life value for human ␤-globin mRNA that exceeds 16 to 20 h. Globin mRNAs survive, and continue to translate at high levels, for as long as a week following nuclear condensation and extrusion in transcriptionally silent erythroid progenitor cells. As might be anticipated, mutations that impair the normal stabilities of globin mRNAs can severely impact the levels of their encoded proteins. For example, an mRNA-destabilizing mutation reduces the expression of ␣ Constant Spring to less than 2% of normal levels (45,51,80), resulting in a clinically important form of thalassemia characterized by a substantial imbalance in ␣-and ␤-globin chain accumulation (10, 64).The cis-acting determinants and trans-acting factors that participate in regulating ␣-globin mRNA stability have recently been identified, and the relevant molecular mechanisms have been described in detail. Mutational analyses carried out with cultured cells (80, 81) and with animal models (52, 66) clearly demonstrate the importance of the 3Ј untranslated region (3ЈUTR) to the constitutively high stability of ␣-globin mRNA (45). Other studies have mapped this characteristic to a phylogenically conserved, 16-nucleotide (nt) C/U-rich element in this region (39,75,76). The cis-acting pyrimidine-rich element (PRE) assembles an mRNP "␣-complex" that compri...

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Section: Discussionmentioning

confidence: 99%

A Nucleolin-Binding 3′ Untranslated Region Element Stabilizes β-Globin mRNA In Vivo

Jiang¹,

Xu²,

Russell

2006

Molecular and Cellular Biology

107

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“…Therefore, our results argue rather that the pol I promoter contains all of the information required for the repression by nucleolin. It has been shown that nucleolin binds tightly to chromatin (42,43), and to DNA fragments containing the region of the nontranscribed rDNA spacer upstream of the initiation site (19). Furthermore, nucleolin is able to interact with histone H1 and to modulate chromatin structure (20,21) suggesting that nucleolin could mediate repression of transcription through an interaction with the chromosomal intergenic spacer.…”

Section: Discussionmentioning

confidence: 99%

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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“…Nucleolin is highly phosphorylated (Olson et al, 1975;Rao et al, 1982) and its phosphorylation is highly regulated during the cell cycle (Peter et al, 1990;Morimoto et al, 2005). Extensive phosphorylation by casein kinase 2 (CK2) occurs at interphase and by CDC2 during mitosis (Peter et al, 1990), and this regulated phosphorylation of nucleolin probably regulates nucleolin functions during the cell cycle (Ginisty et al, 1999).…”

Section: Journal Of Cell Science 2092mentioning

confidence: 99%

“…As a multifunctional protein, nucleolin has also been proposed to be a nuclear matrix-binding protein (Gotzmann et al, 1997), to interact with telomerase (Khurts et al, 2004) and to be involved in the regulation of apoptosis (Mi et al, 2003), intestinal cell differentiation (Turck et al, 2006) and remodeling of nucleosomes (Angelov et al, 2006). Although many functions of nucleolin have been clarified, previous studies have fallen short of demonstrating its functions during mitosis.Nucleolin is highly phosphorylated (Olson et al, 1975;Rao et al, 1982) and its phosphorylation is highly regulated during the cell cycle (Peter et al, 1990;Morimoto et al, 2005). Extensive phosphorylation by casein kinase 2 (CK2) occurs at interphase and by CDC2 during mitosis (Peter et al, 1990), and this regulated phosphorylation of nucleolin probably regulates nucleolin functions during the cell cycle (Ginisty et al, 1999).…”

mentioning

confidence: 99%

Nucleolin functions in nucleolus formation and chromosome congression

Matsunaga

Takata

et al. 2007

Journal of Cell Science

118

124

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A complex structure, designated the chromosome periphery, surrounds each chromosome during mitosis. Although several proteins have been shown to localize to the chromosome periphery, their functions during mitosis remain unclear. Here, we used a combination of highresolution microscopy and RNA-interference-mediated depletion to study the functions of nucleolin, a nucleolar protein localized at the chromosome periphery, in interphase and mitosis. During mitosis, nucleolin was localized in the peripheral region including the vicinity of the outer kinetochore of chromosomes. Staining with an antibody specific for nucleolin phosphorylated by CDC2 revealed that nucleolin was also associated with the spindle poles from prometaphase to anaphase. Nucleolin depletion resulted in disorganization of the nucleoli at interphase. Furthermore, nucleolin-depleted cells showed a prolonged cell cycle with misaligned chromosomes and defects in spindle organization. The misaligned chromosomes showed syntelic kinetochore-microtubule attachments with reduced centromere stretching. Taken together, our results indicate that nucleolin is required for nucleolus formation, and is also involved in chromosome congression and spindle formation. Journal of Cell Science 2092Nucleolin is an abundant nucleolar protein localized in the DFCs and GCs of nucleoli (Biqqioqera et al., 1990). Nucleolin plays essential roles in rDNA transcription, rRNA maturation, ribosome assembly and nucleocytoplasmic transport (Ginisty et al., 1999;Srivastava and Pollard, 1999). As a multifunctional protein, nucleolin has also been proposed to be a nuclear matrix-binding protein (Gotzmann et al., 1997), to interact with telomerase (Khurts et al., 2004) and to be involved in the regulation of apoptosis (Mi et al., 2003), intestinal cell differentiation (Turck et al., 2006) and remodeling of nucleosomes (Angelov et al., 2006). Although many functions of nucleolin have been clarified, previous studies have fallen short of demonstrating its functions during mitosis.Nucleolin is highly phosphorylated (Olson et al., 1975;Rao et al., 1982) and its phosphorylation is highly regulated during the cell cycle (Peter et al., 1990;Morimoto et al., 2005). Extensive phosphorylation by casein kinase 2 (CK2) occurs at interphase and by CDC2 during mitosis (Peter et al., 1990), and this regulated phosphorylation of nucleolin probably regulates nucleolin functions during the cell cycle (Ginisty et al., 1999). It has been demonstrated that phosphorylation of nucleolin at interphase is correlated with active rRNA transcription (Suzuki et al., 1987). Despite a previous study describing the localization of nucleolin phosphorylated by CDC2 (Dranovsky et al., 2001), no information about its functions during mitosis has been obtained to date.Here, we demonstrate that nucleolin localizes to the nucleoli, which are located in the peripheral region including the vicinity of the outer kinetochore of chromosomes, in interphase nuclei and during mitosis. Staining with an antibody specific for nucle...

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Localization and phosphorylation of nuclear, nucleolar and extranucleolar non-histone proteins of Novikoff hepatoma ascites cells

Cited by 45 publications

References 27 publications

A Nucleolin-Binding 3′ Untranslated Region Element Stabilizes β-Globin mRNA In Vivo

A Nucleolin-Binding 3′ Untranslated Region Element Stabilizes β-Globin mRNA In Vivo

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

Nucleolin functions in nucleolus formation and chromosome congression

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