Meeting Abstract

P3.97  Monday, Jan. 6 15:30  Gene body methylation and gene regulation the coral Acropora millepora DIXON, G.*; MATZ, M.; Univ Texas, Austin; Univ Texas, Austin grovesdixon@gmail.com

DNA methylation is an evolutionarily ancient epigenetic modification found in bacteria, plants, animals and fungi. In invertebrates, DNA methylation is primarily targeted to CpG dinucleotides within transcription units (gene bodies). Genome wide studies of a number of invertebrate species suggest that gene body methylation is involved in transcriptional regulation, chromatin modification, alternative splicing and environmentally induced phenotypes. However, the functional importance of gene body methylation in coral has yet to be thoroughly investigated. Here we present a genome wide study of gene body methylation in the coral species Acropora millepora and Acropora digitifera and its relationship with gene regulation. Because of the increased rate of substitution of methylated cytosines, genes that are targeted for methylation become depleted of CpG dinucleotides over evolutionary time. Using CpG depletion as a predictor for DNA methylation, we found that the genes of both species can be divided into distinct groups of hypermethylated and hypomethylated genes. These methylation groups showed significant enrichment for genes from unique functional categories. Hypermethylated genes were enriched for housekeeping functions such as RNA and DNA metabolism, and hypomethylated genes were enriched for inducible functions, such as cell signaling and developmental processes. Using RNA-seq, we found a clear underlying relationship between CpG depletion and transcription. CpG depletion (hypermethylation) correlated with higher transcription, and CpG enrichment (hypomethylation) correlated with lower transcription. Our results indicate that gene body methylation is common in coral genomes and are suggestive that gene body methylation is involved with gene regulation.