Specific interaction between full-length PSTVd RNA and the tomato protein VirP1. (A) The three full-length PSTVd RNAs that were tested in the three-hybrid system for VirP1 binding. The drawings show where PSTVd(Ha106), PSTVd(Sma), and PSTVd(Sty) are linearized. (B) Results of the β-gal assay. Five RNA hybrids were combined with three protein hybrids, and the respective S. cerevisiae strains were tested for β-gal activity. All five RNA hybrids contain MS2 RNA. Three of them, MS2-PSTVd(Ha106), MS2-PSTVd(Sma), and MS2-PSTVd(Sty), contain additionally PSTVd(Ha106), PSTVd(Sma), and PSTVd(Sty) RNA, respectively. MS2-IRE contains the iron responsive element. All the three protein hybrids contain the Gal4 activation domain. AD-VirP1ct additionally contains a 313-amino-acid carboxy-terminal fragment of VirP1. AD-IRP contains the iron responsive protein.
