DNA methylation reprogramming in teleosts

• Published in: Evolution & development 2024-09, Vol.26 (5), p.e12486-n/a
• Main Authors: Matlosz, Sébastien, Franzdóttir, Sigríður R., Pálsson, Arnar, Jónsson, Zophonías O.
• Format: Article
• Language: English
• Subjects: Cell lineage; Chemical modification; Chromatin; DNA methylation; DNA structure; Embryogenesis; Epigenetics; evolution; Fertilization; Gene expression; Germ cells; Phenotypic variations; reprogramming; Species richness; teleosts; Transcription factors; Zygotes
• ISSN: 1520-541X; 1525-142X; 1525-142X
• DOI: 10.1111/ede.12486

Early embryonic development is crucially important but also remarkably diverse among animal taxa. Axis formation and cell lineage specification occur due to both spatial and temporal control of gene expression. This complex system involves various signaling pathways and developmental genes such as transcription factors as well as other molecular interactants that maintain cellular states, including several types of epigenetic marks. 5mC DNA methylation, the chemical modification of cytosines in eukaryotes, represents one such mark. By influencing the compaction of chromatin (a high‐order DNA structure), DNA methylation can either repress or induce transcriptional activity. Mammals exhibit a reprogramming of DNA methylation from the parental genomes in the zygote following fertilization, and later in primordial germ cells (PGCs). Whether these periods of methylation reprogramming are evolutionarily conserved, or an innovation in mammals, is an emerging question. Looking into these processes in other vertebrate lineages is thus important, and teleost fish, with their extensive species richness, phenotypic diversity, and multiple rounds of whole genome duplication, provide the perfect research playground for answering such a question. This review aims to present a concise state of the art of DNA methylation reprogramming in early development in fish by summarizing findings from different research groups investigating methylation reprogramming patterns in teleosts, while keeping in mind the ramifications of the methodology used, then comparing those patterns to reprogramming patterns in mammals. DNA methylation reprogramming dynamics in the early embryonic stages (left) and primordial germ cells (right) of zebrafish, medaka, and mouse highlight diversity within and between vertebrate groups.