Published 6 August 2001. doi:10.1083/jcb.200105084
© The Rockefeller University Press,
0021-9525/2001/8/499 $5.00
The Journal of Cell Biology, Volume 154, Number 3, August 6, 2001 499-510
RNA-mediated interaction of Cajal bodies and U2 snRNA genes
Mark R. Frey and
A. Gregory Matera
Department of Genetics and Program in Cell Biology, Case Western Reserve University, Cleveland, OH 44106
Address correspondence to Greg Matera, Department of Genetics, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4955. Tel.: (216) 368-4922. Fax: (216) 368-3432. E-mail: gxm26{at}po.cwru.edu
Cajal bodies (CBs) are nuclear structures involved in RNA metabolism that accumulate high concentrations of small nuclear ribonucleoproteins (snRNPs). Notably, CBs preferentially associate with specific genomic loci in interphase human cells, including several snRNA and histone gene clusters. To uncover functional elements involved in the interaction of genes and CBs, we analyzed the expression and subcellular localization of stably transfected artificial arrays of U2 snRNA genes. Although promoter substitution arrays colocalized with CBs, constructs containing intragenic deletions did not. Additional experiments identified factors within CBs that are important for association with the native U2 genes. Inhibition of nuclear export or targeted degradation of U2 snRNPs caused a marked decrease in the levels of U2 snRNA in CBs and strongly disrupted the interaction with U2 genes. Together, the results illustrate a specific requirement for both the snRNA transcripts as well as the presence of snRNPs (or snRNP proteins) within CBs. Our data thus provide significant insight into the mechanism of CB interaction with snRNA loci, strengthening the putative role for this nuclear suborganelle in snRNP biogenesis.
Key Words: snRNPs; snRNAs; RNU2 loci; nuclear bodies; RNA processing
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