Small RNAs of Nuclear Viroids Figure 4. Most HSVd- and GYSVd1-sRNAs derive from restricted regions of the genomic (+) and (2) RNAs. Location of the 59 termini and frequency of the HSVd-sRNAs (A) and GYSVd1-sRNAs (B) from tendril in their corresponding (+) and (2) genomic RNAs. Positives values correspond to vd-sRNAs of (+) polarity and negative values correspond to the vd-sRNAs of (2) polarity. Note that the scale is different in the panels and that the same numbers are used in the (+) polarity (59R39 orientation is from left to right) and in the (2) polarity (59R39 orientation is from right to left). For the location of the 59 termini of vd-sRNAs we have considered the HSVd and GYSVd1 sequence variant with the accession numbers X06873 [48] and GQ995473, respectively. The viroid sequences covered by vd-sRNAs bellowing to hotspots (HS1, HS2 and HS3 for HSVd and GY1, GY2 and GY3 for GYSVd1) are denoted by arrows whose sense indicates 59R39 orientation. doi:10.1371/journal.pone.0007686.g004 PLoS ONE | www.plosone.org 6 November 2009 | Volume 4 | Issue 11 | e7686