The Kaposi's sarcoma-associated herpesvirus produces a 1077 nucleotide noncoding, polyadenylated, exclusively nuclear RNA called PAN that is highly expressed in lytically infected cells. We report that PAN contains a novel post-transcriptional element essential for its abundant accumulation. The element, PAN-ENE (PAN RNA expression and nuclear retention element), increases the efficiency of 3′-end formation in vivo and is sufficient to enhance RNA abundance from an otherwise inefficiently expressed intronless β-globin construct. The PAN-ENE does not concomitantly increase the production of encoded protein. Rather, it retains the unspliced β-globin mRNA in the nucleus. Tethering of export factors can override the nuclear retention of the PAN-ENE, supporting a mechanism whereby the PAN-ENE blocks assembly of an export-competent mRNP. The activities of the PAN-ENE are specific to intronless constructs, since inserting the PAN-ENE into a spliced β-globin construct has no effect on mRNA abundance and does not affect localization. This is the first characterization of a cis-acting element that increases RNA abundance of intronless transcripts but inhibits assembly of an export-competent mRNP.
- 3′-end formation
- Nuclear retention
- RNA export
ASJC Scopus subject areas
- Molecular Biology
- Biochemistry, Genetics and Molecular Biology(all)
- Immunology and Microbiology(all)