DNA methylation is an epigenetic mechanism with roles that range from the fine tuning
of transcription to genome wide dynamic acclimation to changing environments and
regulation of developmental processes. While recent work has confirmed the presence
and regulatory functions of DNA methylation in non-bilaterians, its role and distribution
in Porifera has never been addressed. In this study, we performed whole genome
bisulfite sequencing of the demosponge Amphimedon queenslandica and show that
DNA methylation occurs mostly in CpG dinucleotides of coding regions. While high levels
of gene-body methylation correlate positively with high expression and co-occur with
the histone modification H3K36me3, they are not associated with amelioration of
spurious transcription as found in other metazoans; nonetheless, per-exon methylation
levels are predictive for exon retention suggesting a role in mRNA splicing. Additionally,
analyses of Amphimedon and other sponges genomic data consistently revealed biased
dinucleotide frequencies that suggest a long history of methylation-driven CpG
conversion. Despite a genome wide loss of CpG dinucleotides, these are positively
selected in exons and in methylated genes. These results indicate DNA methylation as a
component of early metazoans regulome and challenge hypothesis on CpG methylation
acting as a means for codon usage optimization.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/630102 |
| Date | 11 1900 |
| Creators | Ruiz Santiesteban, Juan Antonio |
| Contributors | Aranda, Manuel, Biological and Environmental Sciences and Engineering (BESE) Division, Voolstra, Christian R., Fischle, Wolfgang |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | 2019-11-29, At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis became available to the public after the expiration of the embargo on 2019-11-29. |
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