Small nuclear RNA (snRNA) is a class of small RNA molecules that are found within the splicing speckles and Cajal bodies of the cell nucleus in eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides.

Extranucleolar-nuclear-specific RNAs (snRNA) are 4.5S RNA I, II, III, 5S RNA III, U1, U2, U4, U5, and U6, in addition to over 500 different RNA species reported up to now. In particular, some snoRNAs and snRNAs have trimethylguanosine cap structures that are not present in bacteria.

2020年10月21日 · The 2,2,7-trimethylguanosine (TMG) cap is one of the first identified modifications on eukaryotic RNAs. TMG, synthesized by the conserved Tgs1 enzyme, is abundantly present on snRNAs essential for pre-mRNA splicing. Results from ex vivo experiments in vertebrate cells suggested that TMG ensures nucl …

1990年8月17日 · Antibodies in the cytoplasm against the m 3 G cap inhibited the nuclear uptake of U1 snRNP. U1 RNA that was uncapped or contained an unnatural ApppG cap did not enter the nucleus, even though it carried a normal complement of protein molecules.

2014年1月1日 · The use of a set of modified synthetic cap analogs, including GpppG, m 7 GpppG, m 2 2,7 GpppG, m 3 2,2,7 GpppG, and et 7 GpppG, to analyze their ability to inhibit export of U1 snRNA from Xenopus oocytes nucleus, enabled the researchers to define recognition specificity of a protein factor involved in RNA export (originally referred to as a cap ...

1992年1月1日 · There are more than twenty capped small nuclear RNAs characterized in eukaryotic cells. All the capped RNAs appear to be involved in the processing of other nuclear premessenger or preribosomal RNAs. These RNAs contain either trimethylguanisone (TMG) cap structure or methylated γ phosphate (Mppp) cap structure.

Sm-class RNAs are characterized by a 5′-trimethylguanosine cap, a 3′ stem–loop and a binding site for a group of seven Sm proteins (the Sm site) that form a heteroheptameric ring structure .

1990年8月10日 · The results indicate that nuclear targeting of U1 snRNA requires both a trimethylguanosine cap structure and binding of at least one common U snRNP protein. Using synthetic U6 snRNAs, it is further demonstrated that the trimethylguanosine cap structure can act in nuclear targeting in the absence of the common U snRNP proteins.

The RNA components of small nuclear ribonucleoproteins (U snRNPs) possess a characteristic 5'-terminal trimethylguanosine cap structure (m3G cap). This cap is an important component of the nuclear localization signal of U snRNPs. It arises by hypermethylation of a cotranscriptionally added m7G cap.

1986年9月12日 · Trimethyl capping of U2 snRNA has been studied using U2 genes with mutations located in either the 5′ flanking or the coding region. A monomethyl (7-methylguanosine) cap is added to U2 cotranscriptionally, trimethylation being posttranscriptional.