Laura L McCullough

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FACT has been proposed to function by displacing H2A-H2B dimers from nucleosomes to form hexasomes. Results described here with yeast FACT (yFACT) suggest instead that nucleosomes are reorganized to a form with the original composition but a looser, more dynamic structure. First, yFACT enhances hydroxyl radical accessibility and endonuclease digestion in(More)
yFACT (heterodimers of Saccharomyces cerevisiae Spt16-Pob3 combined with Nhp6) binds to and alters the properties of nucleosomes. The essential function of yFACT is not disrupted by deletion of the N-terminal domain (NTD) of Spt16 or by mutation of the middle domain of Pob3, but either alteration makes yeast cells sensitive to DNA replication stress. We(More)
FACT, a heterodimer of Spt16 and Pob3, is an essential histone chaperone. We show that the H2A-H2B binding activity that is central to FACT function resides in short acidic regions near the C termini of each subunit. Mutations throughout these regions affect binding and cause correlated phenotypes that range from mild to lethal, with the largest individual(More)
FACT (FAcilitates Chromatin Transcription/Transactions) plays a central role in transcription and replication in eukaryotes by both establishing and overcoming the repressive properties of chromatin. FACT promotes these opposing goals by interconverting nucleosomes between the canonical form and a more open reorganized form. In the forward direction,(More)
FACT plays important roles in both gene transcription and DNA replication. However, how this protein complex is targeted to these two distinct cellular processes remains largely unknown. Here we show that ubiquitylation of the Spt16 subunit of FACT by Rtt101, the cullin subunit of an E3 ubiquitin ligase in Saccharomyces cerevisiae, links FACT to DNA(More)
Yeast Blm10 and mammalian PA200 proteins share significant sequence similarity and both cap the ends of 20 S proteasomes and enhance degradation of some peptide substrates. Blm10 was identified as a suppressor of the yeast blm3-1 mutation, and initially was thought to be the Blm3 protein. Both the blm3-1 and blm10-Delta mutations were reported to cause(More)
DNA accessibility to regulatory proteins is substantially influenced by nucleosome structure and dynamics. The facilitates chromatin transcription (FACT) complex increases the accessibility of nucleosomal DNA, but the mechanism and extent of its nucleosome reorganization activity are unknown. Here we determined the effects of FACT from the yeast(More)
The histone chaperone FACT is an essential and abundant heterodimer found in all eukaryotes. Here we report a crystal structure of the middle domain of the large subunit of FACT (Spt16-M) to reveal a double pleckstrin homology architecture. This structure was found previously in the Pob3-M domain of the small subunit of FACT and in the related histone(More)
Saccharomyces cerevisiae Spt6 protein is a conserved chromatin factor with several distinct functional domains, including a natively unstructured 30-residue N-terminal region that binds competitively with Spn1 or nucleosomes. To uncover physiological roles of these interactions, we isolated histone mutations that suppress defects caused by weakening(More)
The pob3-Q308K mutation alters the small subunit of the Saccharomyces cerevisiae histone/nucleosome chaperone FACT, causing defects in both transcription and DNA replication. We describe histone mutations that suppress some of these defects, providing new insight into the mechanism of FACT activity in vivo. FACT is primarily known for its ability to promote(More)