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A synthetic snRNA m3G-CAP enhances nuclear delivery of exogenous proteins and nucleic acids.

Moreno PM, Wenska M, Lundin KE, Wrange O, Strömberg R, Smith CI - Nucleic Acids Res. (2009)

Bottom Line: However, also for small oligonucleotides, achieving higher nuclear concentrations could be of great benefit.The cap is found in the small nuclear RNAs that are constitutive part of the small nuclear ribonucleoprotein complexes involved in nuclear splicing.The synthetic capping of oligos interfering with splicing may have immediate clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, SE-141 86 Huddinge, Sweden. pedro.moreno@ki.se

ABSTRACT
Accessing the nucleus through the surrounding membrane poses one of the major obstacles for therapeutic molecules large enough to be excluded due to nuclear pore size limits. In some therapeutic applications the large size of some nucleic acids, like plasmid DNA, hampers their access to the nuclear compartment. However, also for small oligonucleotides, achieving higher nuclear concentrations could be of great benefit. We report on the synthesis and possible applications of a natural RNA 5'-end nuclear localization signal composed of a 2,2,7-trimethylguanosine cap (m(3)G-CAP). The cap is found in the small nuclear RNAs that are constitutive part of the small nuclear ribonucleoprotein complexes involved in nuclear splicing. We demonstrate the use of the m(3)G signal as an adaptor that can be attached to different oligonucleotides, thereby conferring nuclear targeting capabilities with capacity to transport large-size cargo molecules. The synthetic capping of oligos interfering with splicing may have immediate clinical applications.

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Structure of the 2,2,7-trimethylguanosine cap.
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Figure 1: Structure of the 2,2,7-trimethylguanosine cap.

Mentions: After release in the cytoplasm the U snRNA is recognized by the survival of motor neuron complex (SMN) that directs the proper assembly with a group of Sm proteins (7–10). Subsequently, the m7G cap is hypermethylated to a 5′ 2,2,7-trimethylguanosine (m3G) cap structure (Figure 1) by the small-nuclear RNA cap hypermethylase (11,12). The matured snRNP is then imported back into the nucleus. This nuclear transport involves two different pathways and two very distinct import signals, both of which, however, recruiting importin β (13–16). The first pathway uses a still ill-defined import signal present in the Sm core domain of the snRNP formed by the Sm proteins (17). The second pathway involves the use of the m3G-CAP structure (18). The m3G-CAP signal is recognized by the import adaptor protein snurportin (SPN1) (14,19,20), which in turn is recognized by importin β (14–16,21).Figure 1.


A synthetic snRNA m3G-CAP enhances nuclear delivery of exogenous proteins and nucleic acids.

Moreno PM, Wenska M, Lundin KE, Wrange O, Strömberg R, Smith CI - Nucleic Acids Res. (2009)

Structure of the 2,2,7-trimethylguanosine cap.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665231&req=5

Figure 1: Structure of the 2,2,7-trimethylguanosine cap.
Mentions: After release in the cytoplasm the U snRNA is recognized by the survival of motor neuron complex (SMN) that directs the proper assembly with a group of Sm proteins (7–10). Subsequently, the m7G cap is hypermethylated to a 5′ 2,2,7-trimethylguanosine (m3G) cap structure (Figure 1) by the small-nuclear RNA cap hypermethylase (11,12). The matured snRNP is then imported back into the nucleus. This nuclear transport involves two different pathways and two very distinct import signals, both of which, however, recruiting importin β (13–16). The first pathway uses a still ill-defined import signal present in the Sm core domain of the snRNP formed by the Sm proteins (17). The second pathway involves the use of the m3G-CAP structure (18). The m3G-CAP signal is recognized by the import adaptor protein snurportin (SPN1) (14,19,20), which in turn is recognized by importin β (14–16,21).Figure 1.

Bottom Line: However, also for small oligonucleotides, achieving higher nuclear concentrations could be of great benefit.The cap is found in the small nuclear RNAs that are constitutive part of the small nuclear ribonucleoprotein complexes involved in nuclear splicing.The synthetic capping of oligos interfering with splicing may have immediate clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, SE-141 86 Huddinge, Sweden. pedro.moreno@ki.se

ABSTRACT
Accessing the nucleus through the surrounding membrane poses one of the major obstacles for therapeutic molecules large enough to be excluded due to nuclear pore size limits. In some therapeutic applications the large size of some nucleic acids, like plasmid DNA, hampers their access to the nuclear compartment. However, also for small oligonucleotides, achieving higher nuclear concentrations could be of great benefit. We report on the synthesis and possible applications of a natural RNA 5'-end nuclear localization signal composed of a 2,2,7-trimethylguanosine cap (m(3)G-CAP). The cap is found in the small nuclear RNAs that are constitutive part of the small nuclear ribonucleoprotein complexes involved in nuclear splicing. We demonstrate the use of the m(3)G signal as an adaptor that can be attached to different oligonucleotides, thereby conferring nuclear targeting capabilities with capacity to transport large-size cargo molecules. The synthetic capping of oligos interfering with splicing may have immediate clinical applications.

Show MeSH