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Transcriptional co-activator protein p100 interacts with snRNP proteins and facilitates the assembly of the spliceosome.

Yang J, Välineva T, Hong J, Bu T, Yao Z, Jensen ON, Frilander MJ, Silvennoinen O - Nucleic Acids Res. (2007)

Bottom Line: Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing.The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs.Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, PR China. yangj@tijmu.edu.cn

ABSTRACT
Transcription and pre-mRNA splicing are the key nuclear processes in eukaryotic gene expression, and identification of factors common to both processes has suggested that they are functionally coordinated. p100 protein has been shown to function as a transcriptional co-activator for several transcription factors. p100 consists of staphylococcal nuclease (SN)-like and Tudor-SN (TSN) domains of which the SN-like domains have been shown to function in transcription, but the function of TSN domain has remained elusive. Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing. The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs. In vitro splicing assays revealed that the purified p100, and specifically the TSN domain of p100, accelerates the kinetics of the spliceosome assembly, particularly the formation of complex A, and the transition from complex A to B. Consistently, the p100 protein, as well as the separated TSN domain, enhanced the kinetics of the first step of splicing in an in vitro splicing assay in dose-dependent manner. Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.

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Sequence alignment of the human SPF30, SMN and p100 proteins. Identical and similar amino acids are indicated in black and light shading, respectively. The positions of the Tudor domain in SPF30, SMN and p100 proteins are indicated with gray bars. The positions of Sm-protein-binding domains of SPF30 and SMN are indicated with black bars.
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Figure 6: Sequence alignment of the human SPF30, SMN and p100 proteins. Identical and similar amino acids are indicated in black and light shading, respectively. The positions of the Tudor domain in SPF30, SMN and p100 proteins are indicated with gray bars. The positions of Sm-protein-binding domains of SPF30 and SMN are indicated with black bars.

Mentions: p100 protein consists of four similar domains with homology to the staphylococcal nucleases (SN), followed by a C-terminal Tudor-SN (TSN) domain (26). The SN-like domains of p100 have been implicated in protein interactions, and the SN-like domains of p100 protein recruit CBP and RNA pol II to STAT6 and facilitate the formation of STAT6 enhanceosome (20). The function of p100 TSN domain has remained elusive, but the Tudor domain is 30% homologous to SMN (survival of motor neuron protein) Tudor domain, which functions in the assembly of snRNP complexes and pre-mRNA splicing process (27,28; Figure 6).


Transcriptional co-activator protein p100 interacts with snRNP proteins and facilitates the assembly of the spliceosome.

Yang J, Välineva T, Hong J, Bu T, Yao Z, Jensen ON, Frilander MJ, Silvennoinen O - Nucleic Acids Res. (2007)

Sequence alignment of the human SPF30, SMN and p100 proteins. Identical and similar amino acids are indicated in black and light shading, respectively. The positions of the Tudor domain in SPF30, SMN and p100 proteins are indicated with gray bars. The positions of Sm-protein-binding domains of SPF30 and SMN are indicated with black bars.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1935017&req=5

Figure 6: Sequence alignment of the human SPF30, SMN and p100 proteins. Identical and similar amino acids are indicated in black and light shading, respectively. The positions of the Tudor domain in SPF30, SMN and p100 proteins are indicated with gray bars. The positions of Sm-protein-binding domains of SPF30 and SMN are indicated with black bars.
Mentions: p100 protein consists of four similar domains with homology to the staphylococcal nucleases (SN), followed by a C-terminal Tudor-SN (TSN) domain (26). The SN-like domains of p100 have been implicated in protein interactions, and the SN-like domains of p100 protein recruit CBP and RNA pol II to STAT6 and facilitate the formation of STAT6 enhanceosome (20). The function of p100 TSN domain has remained elusive, but the Tudor domain is 30% homologous to SMN (survival of motor neuron protein) Tudor domain, which functions in the assembly of snRNP complexes and pre-mRNA splicing process (27,28; Figure 6).

Bottom Line: Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing.The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs.Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, PR China. yangj@tijmu.edu.cn

ABSTRACT
Transcription and pre-mRNA splicing are the key nuclear processes in eukaryotic gene expression, and identification of factors common to both processes has suggested that they are functionally coordinated. p100 protein has been shown to function as a transcriptional co-activator for several transcription factors. p100 consists of staphylococcal nuclease (SN)-like and Tudor-SN (TSN) domains of which the SN-like domains have been shown to function in transcription, but the function of TSN domain has remained elusive. Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing. The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs. In vitro splicing assays revealed that the purified p100, and specifically the TSN domain of p100, accelerates the kinetics of the spliceosome assembly, particularly the formation of complex A, and the transition from complex A to B. Consistently, the p100 protein, as well as the separated TSN domain, enhanced the kinetics of the first step of splicing in an in vitro splicing assay in dose-dependent manner. Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.

Show MeSH