Definition of transcriptional pause elements in fission yeast.

Downstream elements (DSEs) with transcriptional pausing activity play an important role in transcription termination of RNA polymerase II. We have defined two such DSEs in Schizosaccharomyces pombe, one for the ura4 gene and a new one in the 3'-end region of the nmt2 gene. Although these DSEs do not have sequence homology, both are orientation specific and are composed of multiple and redundant sequence elements that work together to achieve full pausing activity. Previous studies on the nmt1 and nmt2 genes revealed that transcription extends several kilobases past the genes' poly(A) sites. We show that the insertion of either DSE immediately downstream of the nmt1 poly(A) site induces more immediate termination. nmt2 termination efficiency can be increased by moving the DSE closer to the poly(A) site. These results suggest that DSEs may be a common feature in yeast genes.