A noncanonical bromodomain in the AAA ATPase protein Yta7 directs chromosomal positioning and barrier chromatin activity.
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.
Gradolatto
Angeline
A
University of Arkansas for Medical Sciences, Department of Biochemistry and Molecular Biology, Little Rock, Arkansas 72205, USA.
Smart
Sherri K
SK
Byrum
Stephanie
S
Blair
Lauren P
LP
Rogers
Richard S
RS
Kolar
Elizabeth A
EA
Lavender
Heather
H
Larson
Signe K
SK
Aitchison
John D
JD
Taverna
Sean D
SD
Tackett
Alan J
AJ
D018797:Cell Cycle Proteins / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D045584:Chromosome Positioning; D004843:Epistasis, Genetic; D015966:Gene Expression Regulation, Fungal; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018832:Molecular Chaperones / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000378:metabolism
C109731:ASF1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C071238:SPT16 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035602:Transcriptional Elongation Factors; C508095:YTA7 protein, S cerevisiae