Abstract #76

Nuclear pore association confers optimal expression levels for an inducible yeast gene. Susan Gasser¹, Angela Taddei¹, Florence Hediger², Griet Van Houwe², Veronique Kalck¹, Heiko Schober¹, Cubizolles Fabien¹. 1) Epigenetics, Friedrich Miescher Inst, Basel, CH; 2) University of Geneva, NCCR Frontiers in Genetics, Geneva CH.
   The organization of the nucleus into subcompartments creates micro-environments that are thought to facilitate distinct nuclear functions. In budding yeast, regions of silent chromatin, such as telomeres and mating-type loci, create zones that favor gene repression by clustering at the nuclear envelope. Other reports indicate that gene transcription occurs at the nuclear periphery, apparently due to an association with nuclear pore complexes. Here we report that transcriptional activation of a subtelomeric gene HXK1 by growth on a non-glucose carbon source led to its relocalization to nuclear pores. This relocation required the 3’UTR which is essential for efficient message processing and export. On the other hand, activation of HXK1 by an alternative pathway based on a targeted transactivator VP16 moved the locus away from the nuclear periphery and abrogated the normal induction of HXK1 by galactose. Importantly, when we interfered with HXK1 localization by either antagonizing association with the pore, or promoting it, transcript levels were respectively reduced or enhanced. From this we conclude that nuclear position has an active role in determining optimal gene expression levels.

Return to YGM 2006 Home at SGD