真核生物组蛋白乙酰化是一类重要的表观遗传修饰，调控基因转录、DNA复制、重组和修复等基本生命过程。对植物组蛋白乙酰化的研究多集中在拟南芥H3乙酰化及其催化酶的生物功能上，而其它组蛋白的乙酰化对植物生长发育也很重要；组蛋白H4功能冗余的乙酰化酶HAM1，2的纯合双突变胚胎致死，导致H4乙酰化的功能研究难以深入进行。本项目利用HAM的互作蛋白来研究其介导的H4乙酰化在植物生长发育中的作用，筛选到HAM的互作同源蛋白HIP1和HIP2。hip1:hip2双突变体内组蛋白H4乙酰化严重下调，叶绿体发育异常，提示HIP1和HIP2介导的H4乙酰化调控叶绿体发育。为明确其功能和作用机理，将通过深度测序确定HIP1和HIP2对mRNA转录及基因组水平H4乙酰化的作用，明确植物中H4乙酰化与基因转录的关系以及HIP1和HIP2在叶绿体发育过程中直接调控的靶标基因，阐述H4乙酰化修饰在植物生长发育中的功能。

Histone acetylation is one of the most important epigenetic modifications in eukaryotic organisms and involves in the processes of gene transcription regulation, DNA replication, recombination and repair, etc. Previous functional studies mainly focus on the histone H3 acetylation and the enzymes catalyzing this specific post-translational modification in Arabidopsis. However, the functional consequence of HAM1, HMA2 and HAMs-derived H4 acetylation is largely unknown due to the embryonic lethality caused by ham1:ham2 double mutant. Here, we plan to study the functions of HAM in H4 acetylation through HAM-interacting proteins (HIPs). We have identified HIP1 and HIP2, two homologous proteins using yeast two-hybrid screening. Comparing to WT, the hip1:hip2 double mutant decreased in histone H4 acetylation level with the disrupted chloroplast structures observed under transmission electronic microscope. These data suggested that HIP1 and HIP2 play important roles in regulating chloroplast development through HAM-mediated H4 acetylation. In this project, transcriptome deep-sequencing and ChIP-sequencing will be performed to analyze the function of HIPs in regulating mRNA transcription and the H4 acetylation status of the Arabidopsis genome, so as to elucidate the association between H4 acetylation and gene transcription as well as the directly affected genes in the plant chloroplast development，and provide clues for the understanding of H4 acetylation in the plant growth and development.