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Decreased dicer expression enhances SRP-mediated protein targeting.

Ren YF, Li G, Xue YF, Zhang XJ, Song YJ, Lv L, Wu J, Fang YX, Wang YQ, Shi KQ, Chen YP, Tang KF - PLoS ONE (2013)

Bottom Line: Here we addressed the molecular functions of these 7SL RNA fragments and found that some of them functioned as dominant-negative regulators of the full-length 7SL RNA, interfering with signal recognition particle (SRP) complex formation.These results suggest that some Dicer-processed 7SL RNA fragments interfered with SRP-mediated protein targeting.Moreover, we showed that Dicer knockdown enhanced SRP-mediated protein targeting and that transfection of a mixture of the 7SL RNA fragments partially restored this effect.

View Article: PubMed Central - PubMed

Affiliation: Institute of Genomic Medicine, Wenzhou Medical College, Wenzhou, Zhejiang Province, PR China.

ABSTRACT
We have shown that Dicer processes 7SL RNA into different fragments ranging from ∼20 to more than 200 nucleotides. Here we addressed the molecular functions of these 7SL RNA fragments and found that some of them functioned as dominant-negative regulators of the full-length 7SL RNA, interfering with signal recognition particle (SRP) complex formation. Transfection of these 7SL RNA fragments inhibited the expression of cell surface glycoproteins, the targeting of a reporter protein to the endoplasmic reticulum, and the secretion of secreted alkaline phosphatase. These results suggest that some Dicer-processed 7SL RNA fragments interfered with SRP-mediated protein targeting. Moreover, we showed that Dicer knockdown enhanced SRP-mediated protein targeting and that transfection of a mixture of the 7SL RNA fragments partially restored this effect. Our data indicate that Dicer can fine-tune the efficiency of SRP-mediated protein targeting via processing a proportion of 7SL RNA into fragments of different lengths.

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Effects of the 7SL RNA fragments on the formation of the SRP complex.Glycerol gradient fractionation of postnuclear extracts treated with either the 7SL RNA fragment or the control RNA (LacZ). Upper panel: The relative amount of 7SL RNA in each fraction. The sum of all fractions was set to 100%, and data are shown as mean ± SE from five independent experiments. Lower panel: representative image of western blotting analysis.
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pone-0056950-g002: Effects of the 7SL RNA fragments on the formation of the SRP complex.Glycerol gradient fractionation of postnuclear extracts treated with either the 7SL RNA fragment or the control RNA (LacZ). Upper panel: The relative amount of 7SL RNA in each fraction. The sum of all fractions was set to 100%, and data are shown as mean ± SE from five independent experiments. Lower panel: representative image of western blotting analysis.

Mentions: We then tested whether these 7SL RNA fragments interfere with the formation of the SRP complex. Postnuclear extracts incubated with the control RNA or 7SL RNA fragments were fractionated on glycerol gradients. As shown in Fig. 2, after incubation with the control RNA, most SRP54 and SRP68 proteins migrated in fractions 5 to 7 together with 7SL RNA. These SRP subunits and the full-length 7SL RNA shifted to the upper fractions after treatment with the synthetic 7SL RNA fragments, suggesting that part of the SRP complex may dissociate and hence migrate at lower sedimentation rates.


Decreased dicer expression enhances SRP-mediated protein targeting.

Ren YF, Li G, Xue YF, Zhang XJ, Song YJ, Lv L, Wu J, Fang YX, Wang YQ, Shi KQ, Chen YP, Tang KF - PLoS ONE (2013)

Effects of the 7SL RNA fragments on the formation of the SRP complex.Glycerol gradient fractionation of postnuclear extracts treated with either the 7SL RNA fragment or the control RNA (LacZ). Upper panel: The relative amount of 7SL RNA in each fraction. The sum of all fractions was set to 100%, and data are shown as mean ± SE from five independent experiments. Lower panel: representative image of western blotting analysis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585229&req=5

pone-0056950-g002: Effects of the 7SL RNA fragments on the formation of the SRP complex.Glycerol gradient fractionation of postnuclear extracts treated with either the 7SL RNA fragment or the control RNA (LacZ). Upper panel: The relative amount of 7SL RNA in each fraction. The sum of all fractions was set to 100%, and data are shown as mean ± SE from five independent experiments. Lower panel: representative image of western blotting analysis.
Mentions: We then tested whether these 7SL RNA fragments interfere with the formation of the SRP complex. Postnuclear extracts incubated with the control RNA or 7SL RNA fragments were fractionated on glycerol gradients. As shown in Fig. 2, after incubation with the control RNA, most SRP54 and SRP68 proteins migrated in fractions 5 to 7 together with 7SL RNA. These SRP subunits and the full-length 7SL RNA shifted to the upper fractions after treatment with the synthetic 7SL RNA fragments, suggesting that part of the SRP complex may dissociate and hence migrate at lower sedimentation rates.

Bottom Line: Here we addressed the molecular functions of these 7SL RNA fragments and found that some of them functioned as dominant-negative regulators of the full-length 7SL RNA, interfering with signal recognition particle (SRP) complex formation.These results suggest that some Dicer-processed 7SL RNA fragments interfered with SRP-mediated protein targeting.Moreover, we showed that Dicer knockdown enhanced SRP-mediated protein targeting and that transfection of a mixture of the 7SL RNA fragments partially restored this effect.

View Article: PubMed Central - PubMed

Affiliation: Institute of Genomic Medicine, Wenzhou Medical College, Wenzhou, Zhejiang Province, PR China.

ABSTRACT
We have shown that Dicer processes 7SL RNA into different fragments ranging from ∼20 to more than 200 nucleotides. Here we addressed the molecular functions of these 7SL RNA fragments and found that some of them functioned as dominant-negative regulators of the full-length 7SL RNA, interfering with signal recognition particle (SRP) complex formation. Transfection of these 7SL RNA fragments inhibited the expression of cell surface glycoproteins, the targeting of a reporter protein to the endoplasmic reticulum, and the secretion of secreted alkaline phosphatase. These results suggest that some Dicer-processed 7SL RNA fragments interfered with SRP-mediated protein targeting. Moreover, we showed that Dicer knockdown enhanced SRP-mediated protein targeting and that transfection of a mixture of the 7SL RNA fragments partially restored this effect. Our data indicate that Dicer can fine-tune the efficiency of SRP-mediated protein targeting via processing a proportion of 7SL RNA into fragments of different lengths.

Show MeSH