CELLULAR PROTEINS BIND TO MULTIPLE SITES OF THE LEADER REGION OF CAULIFLOWER MOSAIC-VIRUS 35S RNA

UV crosslinking assays were performed to characterize interactions bet ween the leader of the cauliflower mosaic virus (CaMV) 35S RNA and cel lular, cytoplasmic proteins. From turnip, a host for CaMV, three diffe rent proteins, p35, p49, and p100, interacted with multiple binding si tes within the leader. p35 binds to RNA nonspecifically and p49 binds with low specificity, whereas p100 interacts specifically with viral s equences, The expression of the proteins is not induced upon virus inf ection, as there is no difference in the protein pattern between healt hy and infected cell extracts. in a cellular fractionation, p35 and p1 00 remain in the high-speed supernatant whereas p49 cosediments with p olysomes. A possible involvement of these proteins in the translation of the CaMV 35S RNA is discussed. (C) 1996 Academic Press, Inc.