Genome-wide GTL1 binding sites in Arabidopsis thaliana

To understand how GTL1 regulates cell growth, we first identified its potential direct targets by the chromatin immunoprecipitation followed by the hybridization on an Affymetrix Arabidopsis Tiling 1.0R array (ChIP-chip). To enrich the genomic region bound by GTL1 in vivo, we harvested whole aerial parts of 12-day-old gtl1-1 plants complemented with the pGTL:GTL1:GFP constructs and immunoprecipitated the chromatin fragments associated with GTL1-GFP proteins using antibodies against GFP. After applying a cut-off P-values of 0.001of MAT (Model-based analysis of tiling array), we identified a total number of 3,900 putative immediate target genes that showed consistent binding by GTL1. Two IP chips compared to two Input chips.

为阐明GTL1调控细胞生长的分子机制，本研究首先采用染色质免疫共沉淀芯片（ChIP-chip）技术，即通过染色质免疫共沉淀后与Affymetrix拟南芥平铺式1.0R芯片进行杂交的实验流程，筛选其潜在直接靶基因。为富集体内与GTL1结合的基因组区域，我们收集了12日龄、经pGTL:GTL1:GFP载体互补的gtl1-1突变体植株的全地上部分组织，使用抗GFP抗体免疫沉淀与GTL1-GFP融合蛋白结合的染色质片段。以基于模型的平铺阵列分析（Model-based analysis of tiling array，简称MAT）中P值阈值0.001为筛选标准，我们共鉴定得到3900个受GTL1持续结合的推定直接靶基因。本实验设置两组免疫沉淀芯片与两组输入对照芯片进行对照比对分析。