拟南芥组蛋白H3第三位苏氨酸磷酸化的功能研究

组蛋白转录后的修饰是表观遗传学的重要部分之一，这些修饰伴随着特异的生物学功能，随着研究的深入，对甲基化、乙酰化修饰等组蛋白修饰功能有较深入的了解，然而对组蛋白的磷酸化修饰的功能还知之甚少。组蛋白的磷酸化多发生在H3的第3位、第11位苏氨酸以及第10位和第28位的丝氨酸上，这些磷酸化发生在细胞有丝分裂的多个阶段，通过染色体的浓缩和分离状态来调控着基因的表达，具有重要的生物学功能。一方面，生物体内存生着大量的磷酸化激酶，另一方面，组蛋白磷酸化修饰功能的保守性不强，并在基因表达调控中，具有激活或者抑制基因表达的功能，增加了研究的难度。我们发现拟南芥组蛋白H3第三位苏氨酸磷酸化激酶KIN1，具有H3第三位苏氨酸磷酸化酶的活性，突变体kin1具有晚花的表型，开花抑制基因FLC的表达水平上调，而H3第三位苏氨酸磷酸化修饰水平降低，本研究拟继续解读拟南芥组蛋白第三位苏氨酸磷酸化修饰的分子调控机理。

Post-translational modifcations of histone modulate the functional landscape of chromatin and impinge on many DNA-mediated processes. Although many progresses were done in other histone modifications like histone methylation, histone acetylation and so on, the phosphorylation of histone was poorly understood. Certain conserved residues on histone H3, namely Thr3, Thr11, Ser10 and Ser28, are phophorylated during the interphase or mitosis. Phoshorylation of histone H3 is important in transcriptional regulation with condensation and segregation of chromosome. However, many of kinases involved in events appear to evolve differently in metazoan and plants, on the other hand, the mechanistic function of amino acid also differ among the eukaryotes. Moreover, The function of specific histone phoshorylation, dependent on chromatin context combined with other histone mark, has positive and negative roles in transcriptional regulation. Our results show that loss-of-function of KIN1 has later flower deficit， assoicated with upregulated transcriptional level and attenuated H3T3ph at FLC locus. Take together, our project is to understand the molecular mechanisms of Threonine 3 phosphorylation of histone H3 with isolated kin1 mutant in Arabidopsis.