Potyvirus helper component-proteinase self-interaction in the yeast two-hybrid system and delineation of the interaction domain involved

Using the yeast two-hybrid system, a screen was performed for possible inte ractions between the proteins encoded by the 5' region of potyviral genomes [P1, helper component-proteinase (HC-Pro), and P3]. A positive self-intera ction involving HC-Pro was detected with lettuce mosaic virus (LMV) and pot ato virus Y (PVY). The possibility of heterologous interaction between the HC-Pro of LMV and of PW was also demonstrated. No interaction involving eit her the P1 or the P3 proteins was detected. A series of ordered deletions f rom either the N- or C-terminal end of the LMV HC-Pro was used to map the d omain involved in interaction to the 72 N-terminal amino acids of the prote in, a region known to be dispensable for virus viability but necessary for aphid transmission. A similar but less detailed analysis mapped the interac ting domain to the N-terminal half of the PW HC-Pro. (C) 1999 Academic Pres s.