Distinct patterns of posttranslational histone modifications can regulate DNA-templated events such as mitosis, transcription, replication, apoptosis, and DNA damage, suggesting the presence of a "histone code" in these nuclear processes. Phosphorylation of histone H2A S129 at sites of DNA double-strand breaks (DSBs) has been implicated in damage repair in yeast. Here, we describe another phosphorylation event on serine 1 (S1) of histone H4; this event is also associated with MMS- or phleomycin-induced DSBs but not with UV-induced DNA damage.
View Article and Find Full Text PDFThe efficient and accurate repair of DNA double strand breaks (DSBs) is critical to cell survival, and defects in this process can lead to genome instability and cancers. In eukaryotes, the Rad52 group of proteins dictates the repair of DSBs by the error-free process of homologous recombination (HR). A critical step in eukaryotic HR is the formation of the initial Rad51-single-stranded DNA presynaptic nucleoprotein filament.
View Article and Find Full Text PDFThe kinetics of TATA-binding protein (TBP) and TFIIB binding were measured on a series of promoter constructs that had varying sequences within and flanking the TATA box. The flanking sequences were found to influence TBP stability even though they do not contact the protein. This occurs by altering the decay rate rather than the association rate.
View Article and Find Full Text PDFSequence blocks within the core region were swapped among RNA polymerase II promoters to explore effects on transcription in vitro. The pair of blocks flanking TATA strongly influenced general transcription, with an additional effect on promoter activation. These flanking elements induced a change in the ratio of activated to basal transcription, whereas swapping TATA and initiator sequences only altered general transcription levels.
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