The v-Rel oncoprotein of the Rev-T retrovirus interacts with a number of cellular proteins in transformed chicken spleen cells including p40/I kappa B alpha, p68c-Rel, hsc70, and the p124 and p115 precursors for the p50 and p52 subunits of NF kappa B. Here we report that v-Rel associates with at least three other cellular proteins of 75-85 kDa in these cells, as well as with a protein related to human RelA. Western blot analysis of v-Rel immune complexes showed cross-reactivity between all of these factors and antibodies raised against Rel sequences, but none appeared to represent isoforms of c-Rel. Synchronization experiments revealed that the expression and/or association of these proteins with v-Rel varied throughout the cell cycle. Combined with the previously described interaction of v-Rel with known members of the Rel family, these studies strengthen the hypothesis that the interaction of v-Rel with multiple Rel-related proteins may be important for the transformation of lymphoid cells.