U bodies are cytoplasmic structures that contain uridine-rich small nuclear ribonucleoproteins and associate with P bodies.

ABSTRACT: Uridine-rich small nuclear ribonucleoproteins (U snRNPs) are involved in key steps of pre-mRNA processing in the nucleus of eukaryotic cells. U snRNPs are enriched in the nucleus in discrete organelles that include speckles, Cajal bodies, and histone locus bodies. However, most U snRNPs are assembled in the cytoplasm, not in the nucleus. Despite extensive biochemical information, little is known about the spatial organization of U snRNPs in the cytoplasm. Here we show that U snRNPs in Drosophila are concentrated in discrete cytoplasmic structures, which we call U bodies, because they contain the major U snRNPs. In addition to snRNPs, U bodies contain essential snRNP assembly factors, suggesting that U bodies are sites for assembly or storage of snRNPs before their import into the nucleus.

SUBMITTER: Liu JL 

PROVIDER: S-EPMC1899408 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature