Study On Interaction And Functional Analysis Of Hitone Demethylase JMJ703 And Chromatin Remodeler CHR729 In Rice

In eukaryote, chromatin contains most of the genetic material. DNA is packaged in chromatin by twining with histone octamer. Gene expression and regulation is an extremely complex process, which require the participation of various epigenetic modification factor. These epigenetic modifications are occurred on the chromatin such as DNA methyation and histone modifications. Histone methylation is an important epigenetic modification. Trimethylation of histone H3 lysine 4 marks actived gene and plays an important role in the process of plant growth and environmental stresses. Chromatin remodeling factors can ensure chromatin structure flexibility to certain conditions change in space from the influence of gene expression and regulation. In addition, chromatin remodeling factiors can be combined with histone modification and aggect the histone modification level of whole genome. The relationship between the remodeling factors and the modifier played a vital roles in the regulation of gene expression in normal life activites. Rice as the classic model of monocot plant is the main food in China. However, the role and the mechanism of chromatin remodeling factors and histone demethylase interactionremain unclear.Here we study on chromatin remodeler CHR729 in rice. Explored the CHR729 regulated gene expression by regulating chromatin structure. In addition, we found CHR729 can interact with JMJ703 in vitro. Also explored the fuction of JMJ703 on regulation of induciable genes.1. We constructed CHR729 complement plants to observe the phenotype, showed reverse phenotype of plant height and leaf color compared to chr729. Absence of CHR729 showed directly relative to phenotype.2. CHR729 regulated a series of transcript factors(TFs). We found the gene expression level of these TFs which participated in stress response including AP2, MADS-box, NAC, C3HC4, WRKY in chr729 mutants, CHR729 complement and wildtype changed. CHR729 was possible indicated participating in bio-stress and abiotic stress response.3. The nucleosome of regulated genes by CHR729 in chr729 mutants showed higher density compared to wildtype by Micrococcal nuclease(MNase) digestion whichindicated that CHR729 regulated gene expression by regulating chromatin stucture.4. JMJ703 and CHR729 was found to be constitutive expression gene after analyzing the gene expression patterns, which indicates the possibility of there interaction between time and space. JMJ703 and CHR729 interaction in vitro was found by yeast two-hybrid. The 1-139 aa peptide of JMJ703 could combined with the 791-1046 aa peptide in ATPase binding domain of CHR729, which was found to be the interaction site. Pull-down in vitro also confirmed the interaction.5. The results showed down-regulation of P450 and TPS in JMJ703 over-expressed plant compared to wild-type by Me JA pre-treated. JMJ703 was confirmed to directly regulate expression of JA inducible genes in JMJ703-GR plants. However, Me JA induction of wild type and CHR729 over-expressed plant showed no obviously change, these may be because they are not direclty controled by CHR729.6. Study on jmj703chr729 double mutant phonotype shows more chr729 mutant phonotype. Increased expression level of Cytokinin oxidase(CKX) may be one of the reason that cause abnormal development.