Institut de Biologie Moléculaire des Plantes, UPR2357 CNRS, Université de Strasbourg Strasbourg, France.
Front Plant Sci. 2014 Mar 13;5:83. doi: 10.3389/fpls.2014.00083. eCollection 2014.
Polyubiquitin chain deposition on a target protein frequently leads to proteasome-mediated degradation whereas monoubiquitination modifies target protein property and function independent of proteolysis. Histone monoubiquitination occurs in chromatin and is in nowadays recognized as one critical type of epigenetic marks in eukaryotes. While H2A monoubiquitination (H2Aub1) is generally associated with transcription repression mediated by the Polycomb pathway, H2Bub1 is involved in transcription activation. H2Aub1 and H2Bub1 levels are dynamically regulated via deposition and removal by specific enzymes. We review knows and unknowns of dynamic regulation of H2Aub1 and H2Bub1 deposition and removal in plants and highlight the underlying crucial functions in gene transcription, cell proliferation/differentiation, and plant growth and development. We also discuss crosstalks existing between H2Aub1 or H2Bub1 and different histone methylations for an ample mechanistic understanding.
多聚泛素链在靶蛋白上的沉积通常导致蛋白酶体介导的降解，而单泛素化修饰靶蛋白的性质和功能而不依赖于蛋白水解。组蛋白单泛素化发生在染色质中，目前被认为是真核生物中一种关键的表观遗传标记类型。虽然 H2A 单泛素化（H2Aub1）通常与 Polycomb 途径介导的转录抑制有关，但 H2Bub1 参与转录激活。H2Aub1 和 H2Bub1 的水平通过特定酶的沉积和去除来动态调节。我们综述了植物中 H2Aub1 和 H2Bub1 沉积和去除的动态调节的已知和未知知识，并强调了其在基因转录、细胞增殖/分化以及植物生长发育中的关键功能。我们还讨论了 H2Aub1 或 H2Bub1 与不同组蛋白甲基化之间存在的串扰，以充分了解其机制。
