DNA methyltransferase 3a mediates developmental thermal plasticity

Area of Science:

• Evolutionary biology
• Developmental biology
• Epigenetics

Background:

• Thermal plasticity is crucial for adaptation to changing climates.
• DNA methylation, particularly via DNA methyltransferase 3 (DNMT3) enzymes, may influence environmental responses.
• Developmental plasticity can interact with adult acclimation to improve fitness.

Purpose of the Study:

• To investigate the causative relationship between DNMT3 enzymes and developmental thermal plasticity.
• To determine if DNMT3 enzymes interact with short-term acclimation in zebrafish.
• To assess the impact on fitness and thermal responses.

Main Methods:

• Development of a novel DNMT3a knock-out zebrafish model.
• Sequential knock-out of DNMT3a isoforms (DNMT3aa-/- and DNMT3aa-/-ab-/-).
• Assessment of offspring survival, deformities, thermal performance curves, and citrate synthase activity.

Main Results:

• DNMT3a knock-out additively decreased survival and increased deformities under mismatched temperatures.
• Parental short-term cold acclimation rescued DNMT3a knock-out offspring survival.
• DNMT3a genotype interacted with developmental temperature to modify thermal performance and citrate synthase sensitivity.

Conclusions:

• DNMT3a is essential for regulating developmental thermal plasticity, with additive effects from different isoforms.
• DNMT3a interacts with acclimation mechanisms like histone modification to buffer phenotypes.
• These interactions enhance phenotypic compensation for climate change, reducing costs of environmental mismatches.