Contribution of the serine 129 of histone H2A to chromatin structure.
Phosphorylation of a yeast histone H2A at C-terminal serine 129 has a central role in double-strand break repair. Mimicking H2A phosphorylation by replacement of serine 129 with glutamic acid (hta1-S129E) suggested that phosphorylation destabilizes chromatin structures and thereby facilitates the access of repair proteins. Here we have tested chromatin structures in hta1-S129 mutants and in a C-terminal tail deletion strain. We show that hta1-S129E affects neither nucleosome positioning in minichromosomes and genomic loci nor supercoiling of minichromosomes. Moreover, hta1-S129E has no effect on chromatin stability measured by conventional nuclease digestion, nor does it affect DNA accessibility and repair of UV-induced DNA lesions by nucleotide excision repair and photolyase in vivo. Similarly, deletion of the C-terminal tail has no effect on nucleosome positioning and stability. These data argue against a general role for the C-terminal tail in chromatin organization and suggest that phosphorylated H2A, gamma-H2AX in higher eukaryotes, acts by recruitment of repair components rather than by destabilizing chromatin structures.
Fink
Michel
M
Institute of Cell Biology, ETH Zurich, Schafmattstrasse 18, 8093 Zurich, Switzerland.
Imholz
Daniela
D
Thoma
Fritz
F
D002843:Chromatin / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D043171:Chromosomal Instability; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000378:metabolism; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000737:chemistry / Q000378:metabolism*; D014466:Ultraviolet Rays
D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D012694:Serine