Species-specific interaction of transcription factor p70 with the rDNA core promoter

p70 is a transcription factor that is involved in the initiation of transcr iption by RNA polymerase I and has been shown to cooperate with the selecti vity factor SL1 for binding to the core promoter region of mammalian riboso mal RNA gene (rDNA). To examine a role of the p70-SL1 interaction in promot er recognition, mouse and human proteins were partially purified and analyz ed by W-cross linking. Mouse rDNA core promoter was recognized by any combi nation of p70 and SL1 prepared from either species. In contrast, human p70 no longer bound to the human core promoter when mouse SL1 was used. Thus, a species-specific interaction between p70 and SL1 may be involved in the pr omoter selection for rDNA transcription. (C) 2001 Academic Press.