Evolution of plant PWO proteins and their function: a synthetic biology approach

The Polycomb Group (PcG) proteins ensure the accuracy of developmental processes and maintain cellular identities in both plants and animals.

Among the PcG proteins, Polycomb Repressive Complex 2 (PRC2) establishes the repressive state of targeted genes by introducing the H3K27me3 epigenetic mark.

Recently, a novel PWWP DOMAIN INTERACTOR OF POLYCOMBS 1 (PWO1) protein has been identified as a recruiter and regulator of PRC2. PWO1 may also act as a mediator of PRC2 repression at the nuclear periphery (NP).

Even though PRC2 orthologues are highly conserved from unicellular algae to modern plants, the PWO-like proteins do not seem to follow the same evolutionary pattern as they exclusively arise at a specific time in plant evolution, coinciding with the colonization of land and emergence of vascular systems.

This poses the question of how PWO-like proteins shaped the evolution of the PcG pathway and contributed to plant evolution in a developmental context.

To answer this, I plan to apply a synthetic biology approach with the aim to assess the impact of PWO-like proteins on PWO-less species, particularly to understand whether PWOs can reprogram PRC2 epigenetic activities.

Furthermore, the inspection of ancestral PWOs functions in modern plants will provide essential information regarding the conservation of their activity, for instance, the PWO-mediated link of chromatin repression to the NP across the species.

Lastly, the exploration of unknown interacting partners of PWO-like proteins in both ancestral and modern plants will give insights for the conservation and functions of the PWO-related protein network in PRC2 regulation.

Altogether, this project will shed light on the potential mechanisms underlying the enrolment of PWOs function in developmental epigenetics during land plant evolution.

The acquired expertise through the proposed project will be crucial for me to work as an independent researcher in the area of plant epigenetics and evolutionary biology.