Journal of General Virology

Identification and characterization of a new intron in Borna disease virus

Beatrice Cubitt, Calvin Ly and Juan Carlos de la Torre

The Scripps Research Institute, Department of Neuropharmacology IMM-6, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA

Borna disease virus (BDV) has a non-segmented, negative-strand (NNS) RNA genome. In contrast to all other known NNS RNA animal viruses, BDV replication and transcription occur in the nucleus of infected cells. Moreover, BDV uses RNA splicing for the regulation of its genome expression. Two introns (I and II), both present in two viral primary transcripts of 2.5 and 7.2 kb, have been reported in BDV. Here, evidence is provided of a new BDV intron, intron III, generated by alternative 3´ splice-site choice. Intron III-spliced mRNAs were detected at early times post-infection and found to be present in cells from different types and species. Intron III-spliced mRNAs have coding capability for two new viral proteins with predicted molecular masses of 8.4 and 165 (p165) kDa. p165 is a deleted form of the BDV L polymerase, containing three RGD motifs and a signal peptide signal that could target it into the secretory pathway. These findings underscore the proteomic complexity exhibited by BDV.

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© 2000 SGM

This article is now available in the March 2001 print issue of JGV (vol. 82, 641–646). The complete issue of the journal may be seen in electronic form on JGV Online.