In a collaboration between the team of Said Hafidh (Laboratory of Pollen Biology, Prague, Czech Republic) and the team of Rémy Merret (Institute of Plant Molecular Biology – IBMP, Strasbourg), an important step has been made in understanding the mechanisms that control messenger RNA (mRNA) translation and plant fertility.
This study, published in The Plant Cell, reveals the role of an essential protein called eIF3E. This protein is part of a large cellular complex (eIF3) that regulates a crucial step in gene expression: translation, the process by which proteins are synthesized from messenger RNAs (mRNAs). Although eIF3E was known to participate in this process, its precise role had remained unclear.
Our work shows that eIF3E acts as a selective regulator: it does not control all RNAs in the same way but instead recognizes specific sequence motifs present in certain mRNAs. Depending on the context, it can either repress or stimulate their translation. This fine-tuned regulation depends on a specific structural domain of the protein (the PCI domain) as well as precise chemical modifications (phosphorylations).
When this domain is deleted or altered, eIF3E can no longer properly interact with its partners. As a result, translation regulation is disrupted, pollen tube growth is impaired, and the organization of cellular membranes is affected. The pollen tube is essential for fertilization in plants.
In summary, this study demonstrates that eIF3E plays a key role in maintaining protein production balance in plant cells. By ensuring accurate and regulated translation of specific mRNAs, it directly contributes to plant fertility.
