The Relationship between SMN, the Spinal Muscular Atrophy Protein, and Nuclear Coiled Bodies in Differentiated Tissues and Cultured Cells

Pj, Young; Le, Tao; N, thi Man; Burghes, Arthur H.M.; Morris, G. M.

doi:10.1006/excr.2000.4858

Cited by 186 publications

(172 citation statements)

References 42 publications

Supporting

Mentioning

152

Contrasting

Unclassified

Order By: Relevance

“…It has been shown previously that treatment of Schwann cells with forskolin causes an increase in coiled (Cajal) bodies. Coiled bodies and SMN usually colocalize with each other, and an increase in SMN expression results in additional coiled bodies (15,19). This may indirectly indicate that gems (SMN nuclear deposits) and coiled bodies can be increased by forskolin treatment, which would be in agreement with our observation of the SMN promoter being inducible with forskolin.…”

Section: Discussionsupporting

confidence: 89%

See 1 more Smart Citation

Identification of a Novel Cyclic AMP-response Element (CRE-II) and the Role of CREB-1 in the cAMP-induced Expression of the Survival Motor Neuron (SMN) Gene

Majumder

Varadharaj

Ghoshal

et al. 2004

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Spinal muscular atrophy, an autosomal recessive disorder, is caused by loss of the SMN1 (survival motor neuron) gene while retaining the SMN2 gene. SMN1 produces a majority of full-length SMN transcript, whereas SMN2 generates mostly an isoform lacking exon 7. Here, we demonstrate a novel cAMP-response element, CRE-II, in the SMN promoter that interacts with the cAMP-response element-binding (CREB) family of proteins. In vitro DNase I protection analysis and in vivo genomic footprinting of the SMN promoter using the brain and liver nuclei from SMN2 transgenic mice revealed footprinting at the CRE-II site. Site-directed mutation of the CRE-II element caused a marked reduction in the SMN promoter activity revealed by transient transfection assay. Activation of the cAMP pathway by dibutyryl cAMP (0.5 mM) alone or in combination with forskolin (20 M) caused a 2-5-fold increase in the SMN promoter activity but had no effect on the CRE-II mutated promoter. Electrophoretic mobility shift assay and a UV-induced DNA-protein crosslinking experiment confirmed that CREB1 binds specifically to the CRE-II site. Transient overexpression of CREB1 protein resulted in a 4-fold increase of the SMN promoter activity. Intraperitoneal injection of epinephrine in mice expressing two copies of the human SMN2 gene resulted in a 2-fold increase in full-length SMN transcript in the liver. Combined treatment with dibutyryl cAMP and forskolin significantly increased the level of both the full-length and exon 7-deleted SMN (exon⌬7SMN) transcript in primary hepatocytes from mice expressing two copies of human SMN2 gene. Similar treatments of type I spinal muscular atrophy mouse and human fibroblasts as well as HeLa cells resulted in an augmented level of SMN transcript. These findings suggest that the CRE-II site in SMN promoter positively regulates the expression of the SMN gene, and treatment with cAMP-elevating agents increases expression of both the full-length and exon⌬7SMN transcript.

show abstract

Section: Discussionsupporting

confidence: 89%

“…The 38-kDa SMN protein is ubiquitously expressed (16 -18) and often localizes in the nuclei as dotlike structures termed gems (18,19). SMN is important in small nuclear ribonucleoprotein biogenesis (20 -24) and has been shown to bind a series of other protein partners (25,26).…”

mentioning

confidence: 99%

Identification of a Novel Cyclic AMP-response Element (CRE-II) and the Role of CREB-1 in the cAMP-induced Expression of the Survival Motor Neuron (SMN) Gene

Majumder

Varadharaj

Ghoshal

et al. 2004

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Transformed bacteria were induced with 1 mM isopropyl-thio-␤-D-thiogalaactoside for 4 h at 37°C. Expressed recombinant proteins were purified from inclusion bodies by sequential extraction with increasing urea concentrations (2, 4, 6, and 8 M) in phosphate-buffered saline as previously described (29).…”

Section: Methodsmentioning

confidence: 99%

A Direct Interaction between the Survival Motor Neuron Protein and p53 and Its Relationship to Spinal Muscular Atrophy

Young¹,

Day²,

Zhou³

et al. 2002

Journal of Biological Chemistry

Self Cite

112

View full text Add to dashboard Cite

Mutations in the SMN1 (survival motor neuron 1) gene cause spinal muscular atrophy (SMA). We now show that SMN protein, the SMN1 gene product, interacts directly with the tumor suppressor protein, p53. Pathogenic missense mutations in SMN reduce both self-association and p53 binding by SMN, and the extent of the reductions correlate with disease severity. The inactive, truncated form of SMN produced by the SMN2 gene in SMA patients fails to bind p53 efficiently. SMN and p53 colocalize in nuclear Cajal bodies, but p53 redistributes to the nucleolus in fibroblasts from SMA patients. These results suggest a functional interaction between SMN and p53, and the potential for apoptosis when this interaction is impaired may explain motor neuron death in SMA.Spinal muscular atrophy is a neurodegenerative disorder characterized by loss of the ␣-motor neurons of the spinal cord, resulting in progressive atrophy of the voluntary muscles of the limb and trunk (1). There are three forms of the childhood disease, types I, II, and III, with type I being the most severe. All three forms are due to mutations of the telomeric copy of the SMN1 (survival motor neuron 1) gene (2). The centromeric copy of the SMN gene (SMN2) differs from SMN1 by only 11 nucleotides (2, 3). One of these is a C/T transition located in exon 7 and results in different pre-mRNA splicing patterns; SMN1 produces mainly full-length product, whereas the majority of SMN2-derived transcripts lack exon 7, SMN⌬7 (2-4).SMN is a ubiquitously expressed protein localized within the cytoplasm and the nucleus (2). Nuclear SMN localizes within Cajal bodies (5). Cajal bodies are defined by the presence of p80 coilin (6). Although the precise nature of the motor neuronspecific defect in SMA 1 is not known, the SMN protein has been implicated in several pathways, including nucleo-cytoplasmic transportation, UsnRNP assembly, transcription, and apoptosis (7). SMN can serve as an anti-apoptotic factor in neuronal cells, whereas SMN⌬7 and C-terminal missense mutations promote apoptosis (8). The means by which SMN achieves pro-and anti-apoptotic activities are not known. SMN self-association is a prerequisite for essentially all SMN functions (9 -13). The SMN protein self-associates independently through regions encoded by exons 2b and 6, and the ability to homodimerize correlates with disease severity (14, 15). The primary product of SMN2, SMN⌬7, lacks exon 7, and the resultant protein has a reduced ability to self-associate, accounting for the inability of SMN2 to compensate for the loss of SMN1 (15). The tumor suppressor protein p53 is multifunctional factor involved in cell cycle control (16), DNA repair (17, 18), transcription activation (19,20), and apoptosis (21). p53 can induce apoptosis through several pathways, including mechanisms that are dependent or independent of p53-mediated transcriptional activity (21,22). Under normal physiological conditions, p53 protein levels are maintained at relatively low levels through a negative feedback loop mediated by HDM2 (23-25). ...

show abstract

“…CBs are absent from spermatocytes and from germline stem cells in the female germarium of Drosophila (Liu et al, 2009). CBs are absent or are difficult to demonstrate in some adult vertebrate tissues (Young et al, 2000), whereas they are prominent in others, such as nerve cells (Pena et al, 2001). It is reasonable to suppose that snRNA modification and splicing occur in all of these normal cells that lack CBs.…”

Section: Scarnas In the Nucleoplasm?mentioning

confidence: 99%

Small Cajal Body–specific RNAs ofDrosophilaFunction in the Absence of Cajal Bodies

Deryusheva

Gall

2009

MBoC

View full text Add to dashboard Cite

During their biogenesis small nuclear RNAs (snRNAs) undergo multiple covalent modifications that require guide RNAs to direct methylase and pseudouridylase enzymes to the appropriate nucleotides. Because of their localization in the nuclear Cajal body (CB), these guide RNAs are known as small CB-specific RNAs (scaRNAs). Using a fluorescent primer extension technique, we mapped the modified nucleotides in Drosophila U1, U2, U4, and U5 snRNAs. By fluorescent in situ hybridization (FISH) we showed that seven Drosophila scaRNAs are concentrated in easily detectable CBs. We used two assays based on Xenopus oocyte nuclei to demonstrate that three of these Drosophila scaRNAs do, in fact, function as guide RNAs. In flies null for the CB marker protein coilin, CBs are absent and there are no localized FISH signals for the scaRNAs. Nevertheless, biochemical experiments show that scaRNAs are present at normal levels and snRNAs are properly modified. Our experiments demonstrate that several scaRNAs are concentrated as expected in the CBs of wild-type Drosophila, but they function equally well in the nucleoplasm of mutant flies that lack CBs. We propose that the snRNA modification machinery is not limited to CBs, but is dispersed throughout the nucleoplasm of cells in general. INTRODUCTIONThe two major ribosomal RNAs (rRNAs) and the spliceosomal small nuclear RNAs (snRNAs) U1, U2, U4, U5, and U6 contain many posttranscriptionally modified nucleotides, which are crucial for RNA-RNA and RNA-protein interactions, as well as spliceosome function (Yu et al., 1998; Yu, 2004, 2007). The most abundant modifications in both rRNAs and snRNAs are 2Ј-O-methylation and pseudouridylation, which are directed by small box C/D and box H/ACA guide RNAs, respectively. Each guide RNA molecule is associated with a set of four core proteins: box C/D RNAs form RNP particles with fibrillarin (the methyltransferase), Nop56, Nop58, and a 15.5-kDa protein, whereas box H/ACA RNAs associate with NAP57/dyskerin (the pseudouridine synthase), GAR1, NHP2, and NOP10 proteins (reviewed in Yu et al., 2004;Matera et al., 2007). Most guide RNAs are concentrated in the nucleolus, where they are involved in posttranscriptional modifications of rRNA. Because of their localization, they are referred to as small nucleolar RNAs (snoRNAs). However, the guide RNAs that mediate modification of the snRNAs are preferentially found in another nuclear organelle, the Cajal body (CB). These guide RNAs are called small CB-specific RNAs (scaRNAs).The first scaRNA to be studied in detail was U85 scaRNA (Jády and Kiss, 2001;Darzacq et al., 2002). U85 is a remarkable double guide RNA that contains both box C/D and box H/ACA motifs. In a set of detailed experiments it was shown that human U85 scaRNA guides both 2Ј-O-methylation at C45 and pseudouridylation at U46 in U5 snRNA. Modification takes place in the nucleus after import of the U5 snRNA from the cytoplasm . CB localization of U85 scaRNA was originally demonstrated by fluorescent in situ hybridization (FISH) in mammalian and ...

show abstract

The Relationship between SMN, the Spinal Muscular Atrophy Protein, and Nuclear Coiled Bodies in Differentiated Tissues and Cultured Cells

Cited by 186 publications

References 42 publications

Identification of a Novel Cyclic AMP-response Element (CRE-II) and the Role of CREB-1 in the cAMP-induced Expression of the Survival Motor Neuron (SMN) Gene

Identification of a Novel Cyclic AMP-response Element (CRE-II) and the Role of CREB-1 in the cAMP-induced Expression of the Survival Motor Neuron (SMN) Gene

A Direct Interaction between the Survival Motor Neuron Protein and p53 and Its Relationship to Spinal Muscular Atrophy

Small Cajal Body–specific RNAs ofDrosophilaFunction in the Absence of Cajal Bodies

Contact Info

Product

Resources

About