Swi-Snf and Tup1-Cyc8 cooperate to antagonistically regulate gene transcription in yeast.

Conversely, other co-regulated genes are actively transcribed in wt at levels mediated by the net negative influence of CYC8 and the positive influence of SNF2. In all cases, co-regulated genes located nearest to telomeres are subject to the most robust regulation by Swi-Snf and Tup1-Cyc8. ChIP analysis suggests that Snf2p and Cyc8p are present at both the active and inactive co-regulated genes in wt, where SNF2 is required for full Tup1p occupancy.

We show that Snf2p and Cyc8p can directly interact with each other, most likely in the context of their respective complexes, suggesting that Swi-Snf and Tup1-Cyc8 are present together at co-regulated genes. We demonstrate that the nucleosome remodelling activities by Swi-Snf and Tup1-Cyc8 are specific to each target gene and extend over the available upstream intergenic region, the length of which is dependent upon the genes chromosomal context.

Together, these data/ provide a deeper insight into the interplay between Tup1-Cyc8 and Swi-Snf upon transcription regulation and /suggest their occupancy and activity are intimately intertwined to yield the target gene transcriptional outcome via chromosomal location-dependent chromatin remodelling covering the available upstream gene regions.