The transcription termination site for yeast RNA polymerase I requires
not only an 11 bp binding site for Reb1p, but also about 46 bp of 5'
flanking sequence. We propose that Reb1p bound to its site is part of
a pause element, while the 5' flanking sequence contains a release ele
ment. Pausing requires little other than the DNA-binding domain of Reb
1p and is not specific for polymerase I. The release element, however,
can be polymerase specific. We propose a general model for eukaryotic
transcription terminators in which termination occurs when a relative
ly nonspecific signal induces polymerase to pause in the context of a
release element.