U1 and U2 small nuclear RNAs are present in nuclear speckles

Sui Huang, David L. Spector*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


The localization of UI and U2 small nuclear RNAs (snRNAs) has been examined by in situ hybridization using 2′-O-alkyl oligonucleotide probes. We have found that these snRNAs, which are essential for pre-mRNA splicing, localize in a speckled distribution, in addition to being present in three or four foci, in HeLa cell nuclei. However, in cells of defined passage, such as Detroit 551 and WI-38 fibroblasts, these snRNAs are concentrated in nuclear speckles, and foci are not observed. The speckled distribution of U1 and 112 snRNAs is coincident with the speckled regions enriched in small nuclear ribonucleoprotein particle (snRNP) proteins and the essential non-snRNP splicing factor SC-35. The localization of these key components of the pre-mRN A splicing machinery to speckled nuclear regions suggests that these regions may be involved in pre-mRNA splicing.

Original languageEnglish (US)
Pages (from-to)305-308
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - 1992


  • Nuclear organization
  • RNA processing

ASJC Scopus subject areas

  • General


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