RESUMO
The spatial and temporal control of histone modifications is crucial for precise regulation of chromatin structure and function. Here we report that phosphorylation of H2A at threonine 119 (T119) is enriched at centromere regions in Drosophila mitosis. We found that the Aurora B kinase complex is essential for this phosphorylation at centromeres, while Polo kinase is required to down-regulate H2A phosphorylation on chromosome arms in mitosis. Cyclin B degradation triggers loss of centromeric H2A phosphorylation at anaphase onset. Epistasis analysis indicated that Polo functions upstream of the H2A kinase NHK-1 but parallel to Aurora B. Therefore, multiple mitotic kinases work together to specify the spatial and temporal pattern of H2A T119 phosphorylation.
Assuntos
Centrômero/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/fisiologia , Histonas/metabolismo , Protamina Quinase/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Aurora Quinases , Centrômero/química , Drosophila/citologia , Drosophila/genética , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/genética , Histonas/análise , Mitose , Fosforilação , Protamina Quinase/antagonistas & inibidores , Protamina Quinase/genética , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genéticaRESUMO
TBP-related factor 2 (TRF2), one of the TBP family proteins, is involved in various cellular functions through its transcription stimulation activity. We previously reported that TRF2 is involved in reduction of wee1 mRNA in genotoxin-treated chicken cells. In this study, we investigated the role of TRF2 in wee1 gene expression. It was found that wee1 mRNA was decreased in hydroxyurea-treated NIH3T3 cells. Mouse wee1 promoter activity was repressed by TRF2 in mouse and chicken cells. Chromatin immunoprecipitation and plasmid immunoprecipitation analyses revealed that TRF2 is recruited to the wee1 promoter in accordance with the transcriptional repression. A mutant TRF2 that lacks TFIIA-binding capacity lost its repressive function. This mutant was less recruited to the wee1 promoter than was the wild-type one, and provided a decline in promoter-recruited TFIIA. Data in this study suggest that transcription repressive activity of TRF2 to wee1 promoter needs association with the promoter and TFIIA.
