1. A noncanonical bromodomain in the AAA ATPase protein Yta7 directs chromosomal positioning and barrier chromatin activity.
- Author
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Gradolatto A, Smart SK, Byrum S, Blair LP, Rogers RS, Kolar EA, Lavender H, Larson SK, Aitchison JD, Taverna SD, and Tackett AJ
- Subjects
- Cell Cycle Proteins metabolism, Chromosomal Proteins, Non-Histone metabolism, Epistasis, Genetic, Gene Expression Regulation, Fungal, Histones genetics, Histones metabolism, Humans, Molecular Chaperones metabolism, Protein Structure, Tertiary, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins metabolism, Transcription, Genetic, Transcriptional Elongation Factors metabolism, Chromatin metabolism, Chromosomal Proteins, Non-Histone genetics, Chromosome Positioning, Saccharomyces cerevisiae Proteins genetics
- Abstract
Saccharomyces cerevisiae Yta7 is a barrier active protein that modulates transcriptional states at the silent mating locus, HMR. Additionally, Yta7 regulates histone gene transcription and has overlapping functions with known histone chaperones. This study focused on deciphering the functional role of the noncanonical Yta7 bromodomain. By use of genetic and epistasis analyses, the Yta7 bromodomain was shown to be necessary for barrier activity at HMR and to have overlapping functions with histone regulators (Asf1 and Spt16). Canonical bromodomains can bind to acetylated lysines on histones; however, the Yta7 bromodomain showed an association with histones that was independent of posttranslational modification. Further investigation showed that regions of Yta7 other than the bromodomain conferred histone association. Chromatin immunoprecipitation-chip analyses revealed that the Yta7 bromodomain was not solely responsible for histone association but was also necessary for proper chromosomal positioning of Yta7. This work demonstrates that the Yta7 bromodomain engages histones for certain cellular functions like barrier chromatin maintenance and particular Spt16/Asf1 cellular pathways of chromatin regulation.
- Published
- 2009
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