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Mammalian nuclei contain foci which are highly enriched in components of the pre‐mRNA splicing machinery.
Author(s) -
CarmoFonseca M.,
Tollervey D.,
Pepperkok R.,
Barabino S. M.,
Merdes A.,
Brunner C.,
Zamore P. D.,
Green M. R.,
Hurt E.,
Lamond A. I.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb07936.x
Subject(s) - snrnp , nucleoplasm , small nuclear rna , biology , cajal body , rna splicing , nucleolus , spliceosome , precursor mrna , microbiology and biotechnology , rna , prp24 , small nuclear ribonucleoprotein , cell nucleus , genetics , nucleus , non coding rna , gene
The organization of the major snRNP particles in mammalian cell nuclei has been analysed by in situ labelling using snRNA‐specific antisense probes made of 2′‐OMe RNA. U3 snRNA is exclusively detected in the nucleolus while all the spliceosomal snRNAs are found in the nucleoplasm outside of nucleoli. Surprisingly, U2, U4, U5 and U6 snRNAs are predominantly observed in discrete nucleoplasmic foci. U1 snRNA is also present in foci but in addition is detected widely distributed throughout the nucleoplasm. An anti‐peptide antibody specific for the non‐snRNP splicing factor U2AF reveals it to have a similar distribution to U1 snRNA. Co‐localization studies using confocal fluorescence microscopy prove that U2AF is present in the snRNA‐containing foci. Antibody staining also shows the foci to contain snRNP‐specific proteins and m3G‐cap structures. The presence of major components of the nuclear splicing apparatus in foci suggests that these structures may play a role in pre‐mRNA processing.