GSE24970
Genome-wide mapping of the HY5-mediated gene networks in Arabidopsis that involve both transcriptional and post-transcriptional regulations: RNA-Seq
LONG HYPOCOTYL 5 (HY5) is a basic leucine zipper transcription factor (TF) that functions downstream of multiple families of photoreceptors. Mutations in the HY5 gene cause a myriad of aberrant phenotypes in Arabidopsis, including elongated hypocotyl, reduced accumulation of pigments, halted chloroplast development in greening hypocotyls, altered root morphology and defective hormonal and stimulus responses. HY5 thus acts as an integrater that links various gene networks to coordinate plant development. Here we report an effort to experimentally map the HY5-mediated gene networks in Arabidopsis by integrating genomic loci occupied by HY5 and HY5-dependent gene expression profiles. Our results indicate HY5 binds to over 9,000 genes, which detectably impact the expression of over 1,100 genes, either positively or negatively. Further, HY5 indirectly regulates many other genes through sub-networks mediated by other regulators. In particular, we show that HY5 regulates eight microRNA (miRNA) genes, which in turn control transcript abundance of specific target genes. Over-expressing the HY5-targeted miR408 resulted in phenotypes that are opposite to hy5 mutants. Together our results revealed both the transcriptional and post-transcriptional components of the HY5-mediated gene networks responsible for the phenotypic complexity in plants. Overall design: DNase I-treated total RNA was prepared from wild type and hy5-215 seedlings grown under wild type light (WL). The mRNA fraction was extracted from total RNA using Dynabeads oligo(dT)25 (Invitrogen) following the manufacturer's directions. First- and second-strand cDNA were generated usingSuperScript II and random hexamer primers. Double-stranded cDNA was fragmented by nebulization and used for mRNA library construction following the manufacturer's protocol (Illumina). Bowtie (Langmead et al., 2009) was used to map the sequence reads to the Arabidopsis genome and only uniquely mapped reads were used in subsequent analyses.