In vivo imaging of histone modification dynamics during ZGA

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K07157
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Genetics/Chromosome dynamics
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Sato Yuko 東京工業大学, 科学技術創成研究院, 助教 (70435882)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: エピジェネティクス / 胚性ゲノム活性化 / ライブイメージング / 転写 / ヒストン修飾

Outline of Final Research Achievements

To visualize the onset of ZGA in living embryos, we injected Fab specific to Ser2 phosphorylated RNA polymerase II (RNAP2 Ser2ph) into fertilized eggs. Fluorescence microscopy showed that RNAP2 Ser2ph-Fab became concentrated in nuclei at around 1024-cell stages, indicating that global gene activation was faithfully detected by our system. We also detected a few RNAP2 Ser2ph foci corresponded to the clusters of miR-430 genes, which are highly expressed in early stages.
To detect changes in the levels of histone modifications during ZGA, modification-specific Fabs were injected with RNAP2 Ser2ph-Fab. We found that H3K27ac was the most dynamically increased along with ZGA. The nuclear accumulation of H3K27ac-Fab started earlier than that of RNAP2 Ser2ph-Fab. In addition, H3K27ac also appeared in miR-430 foci earlier than RNAP2 Ser2ph. Inhibition of bromodomain-containing proteins diminished RNAP2Ser2ph accumulation. These results suggest that H3K27ac promotes ZGA and drives transcription.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

これまで生きた胚の中で発生過程におけるヒストン修飾レベルを調べる方法はなかった。今回初めて転写活性化とヒストン修飾動態を同時に観察することに成功した。本研究で開発した方法は、今後個体レベルでのクロマチン動態研究に貢献することが期待できる。