A comparative study of the two novel ELL associated factors (EAFs) of Arabidopsis thaliana

ELL Associated Factors (EAFs) have been identified as physical interactors of the Eleven Nineteen Lysine Rich in Leukemia (ELL) family of transcription elongation factors in organisms from fission yeast to humans. Different organisms contain one or two homologs of EAFs, which have been shown to share similar functions. We recently reported the identification of two novel EAF orthologs, AtEAF1 and AtEAF2, from Arabidopsis thaliana. However, their functional characterization remains to be elucidated. In the present study, we have performed a comparative analysis of both these homologs. Our results reveal that expression of both these homologs is spatio-temporally regulated in selective tissues of the plant during different stages of plant development. We report for the first time that both AtEAFs form hetero-, but not homodimers in planta. Moreover, the heterodimers display a nucleo-cytoplasmic localization. Null mutants of AtEAF1 or AtEAF2, as well as the double ateaf1 ateaf2 mutant, are phenotypically normal throughout their developmental transitions. Interestingly, the double deletion mutant exhibits a phenotypic defect in the presence of transcription elongation inhibitors, whereas both single mutants resemble wild-type plants, suggesting functional redundancy between AtEAF1 and AtEAF2 under conditions of transcriptional stress. A comprehensive insilico analysis suggests that AtEAFs may share common interaction partners, although unique associations are also predicted. Taken together, our study implies that these two proteins may functionally complement each other and may also have independent roles in plants.

The online version contains supplementary material available at 10.1007/s12298-025-01703-1.