COMPILATION AND ANALYSIS OF VIROID AND VIROID-LIKE RNA SEQUENCES

We have created a catalogue comprising all viroid and viroid-like RNA sequences which to our knowledge have been either published or were av ailable from on-line sequence libraries as of October 1, 1995, In the development of this catalogue nomenclature ambiguities were removed, t he likely ancestral sequence of most species was determined and the mo st stable secondary structures of these sequences were predicted using the MulFold package, Only viroids of PSTVd-type possessed a rod-like secondary structure, while most other viroids adopted branched seconda ry structures, Several viroids have predicted secondary structures tha t include either a Y or cruciform structure reminiscent of the tRNA-li ke end of virus genomes at an extremity, However, it remains unknown w hether or not these predicted structures are adopted in solution, and if they serve a particular function in vivo, Additional information su ch as the position of the self-catalytic domains are included in the c atalogue, An analysis of the data compilated in the catalogue is inclu ded, The catalogue will be available on the world wide web (http://www .callisto.si.usherb.ca/similar to jpperra), on computer disk and in pr inted form, It should provide an excellent reference point for further studies.