1. The nonhistone, N-terminal tail of an essential, chimeric H2A variant regulates mitotic H3-S10 dephosphorylation
- Author
-
Xiaoyuan Song, Josephine Bowen, Wei Miao, Martin A. Gorovsky, and Yifan Liu
- Subjects
DNA Replication ,Saccharomyces cerevisiae Proteins ,animal structures ,Molecular Sequence Data ,Mutant Chimeric Proteins ,Mitosis ,Chimeric gene ,medicine.disease_cause ,Tetrahymena thermophila ,Histones ,Dephosphorylation ,Gene Knockout Techniques ,Protein Phosphatase 1 ,Genetics ,medicine ,Nucleosome ,Amino Acid Sequence ,Phosphorylation ,Phylogeny ,Mutation ,biology ,Tetrahymena ,biology.organism_classification ,Molecular biology ,Nucleosomes ,Protein Structure, Tertiary ,Histone ,embryonic structures ,ras Proteins ,biology.protein ,Protein Processing, Post-Translational ,Research Paper ,Developmental Biology - Abstract
H2A.Y is an essential, divergent Tetrahymena thermophila histone variant. It has a long nonhistone N terminus that contains leucine-rich repeats (LRR) and an LRR cap domain with similarity to Sds22p, a regulator of yeast protein phosphatase 1 (PP1) activity in the nucleus. In growing cells, H2A.Y is incorporated into micronuclei only during S phase, which occurs immediately after micronuclear mitosis. Depletion of H2A.Y causes prolonged retention of mitosis-associated histone H3-S10 phosphorylation and mitotic abnormalities that mimic S10E mutation. In cells where H2A.Y is depleted, an inducible chimeric gene, in which the H2A.Y N terminus is attached to H2A.X, is shown to regulate micronuclear H3-S10 phosphorylation. H2A.Y can also be specifically coimmunoprecipitated with a Tetrahymena PP1 ortholog (Ppo1p). Taken together, these results argue that the N terminus of H2A.Y functions to regulate H3-S10 dephosphorylation. This striking in vivo case of “cross-talk” between a H2A variant and a specific post-translational modification of another histone demonstrates a novel function for a histone variant.
- Published
- 2012