The RNA helicase, eIF4A-1, is required for ovule development and cell size homeostasis in Arabidopsis.

eIF4A is a highly conserved RNA-stimulated ATPase and helicase involved in theinitiation of mRNA translation. The Arabidopsis genome encodes 2 isoforms, one of which (eIF4A-1) is required for the coordination between cell cycle progression and cell size control. A T-DNA mutant line, with reduced eIF4A protein levels, displays slow growth, reduced lateral root formation, delayed flowering and abnormal ovule development. Loss of eIF4A-1 reduces the proportion of mitotic cells in the root meristem and perturbs the relationship between cell size and cell cycle progression. Several cell cycle reporter proteins, particularly those expressed at G2/M, have reduced expression in eif4a-1 mutant meristems. Single eif4a-1 mutants are semi sterile and show aberrant ovule growth, while double eif4a-1 / eif4a-2 homozygous mutants could not be recovered, indicating that eIF4A function is essential for plant growth and development