Biochemical and Biophysical Research Communications, Vol.393, No.3, 461-465, 2010
Cleavage-induced termination in U2 snRNA gene expression
The maturation of many small nuclear RNAs is dependent on RNase III-like endonuclease mediated cleavage, which generates a loading site for the exosome complex that trims the precursor at its 3' end. Using a temperature sensitive Pad l nuclease, here we show that the endonuclease cleavage is equally important in terminating the transcription of the U2 snRNA in Schizosaccharomyces pombe. Using a temperature sensitive Dhp1p 5' -> 3' exonuclease, we demonstrate that it also is an essential component of the termination pathway. Taken together the results support a "reversed torpedoes" model for the termination and maturation of the U2 snRNA; the Pad l endonuclease cleavage provides entry sites for the 3' and 5' exonuclease activities, leading to RNA maturation in one direction and transcript termination in the other. (C) 2010 Elsevier Inc. All rights reserved.