Update of the viroid and viroid-like sequence database: addition of a hepatitis delta virus RNA section.

Recently, we developed and made available an online database that includes all the reported (to our knowledge) viroid and viroid-like RNA sequences [Bussire,F., Lafontaine,D. and Perreault,J.-P. (1996)Nucleic Acids Res.24, 1793-1798]. We report here an update of this catalogue which includes the addition of a new section devoted to human hepatitis delta virus (vHDV) sequences. This new section comprises all available vHDV sequences, irrespective of their completeness, which have been either published or were available from nucleic acid libraries. Additional structural characteristics of the vHDV genome, such as the positions of the self-catalytic domains, the antigen open reading frames, etc., are also included. The catalogue is available on the World Wide Web (see text) in a user-friendly form. It should provide an excellent reference point for further molecular studies of these small circular pathogenic RNAs.