RNA extraction, northern hybridization and primer extension were essentially as described (33, 34) . Lowmolecular weight RNAs were separated on 6% acrylamide gels containing 7M urea and transferred to a Hybond N+ membrane by electrotransfer. High-molecular-weight RNAs were analysed on 1.2% agarose gels and transferred by capillary elution. Oligonucletides used for RNA hybridization and primer extension (W235 and W237) are listed in Supplementary Table S2 . Quantification of northern blots was performed using a Storm 860 PhosohorImager and ImageQuant software (Molecular Dynamics). Dideoxy-DNA sequencing was performed on PCR-templates prepared from genomic yeast DNA using the same primers as for primer extension (W235 and W237) and a fMolSeq kit (Promega) according to manufacturer's instructions.