A Kaposi's sarcoma virus RNA element that increases the nuclear abundance of intronless transcripts.
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 beta-globin construct. The PAN-ENE does not concomitantly increase the production of encoded protein. Rather, it retains the unspliced beta-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 beta-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.
Conrad
Nicholas K
NK
Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06536, USA.
Steitz
Joan A
JA
D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D005914:Globins / Q000096:biosynthesis / Q000235:genetics; D019288:Herpesvirus 8, Human / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D026723:Polyadenylation; D012326:RNA Splicing / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism*; D012514:Sarcoma, Kaposi / Q000235:genetics* / Q000821:virology; D014158:Transcription, Genetic / Q000502:physiology
D012333:RNA, Messenger; D005914:Globins