E2Fb and E2Fa transcription factors independently regulate the DNA damage response after ultraviolet B exposure in Arabidopsis

Abstract

SUMMARY Ultraviolet (UV)B radiation affects plant growth inhibiting cell proliferation. This inhibition is in part controlled by the activity of transcription factors from the E2F family. In particular, the participation of E2Fc and E2Fe in UV‐B responses in Arabidopsis plants was previously reported. However, the E2Fa and E2Fb contribution to these processes has still not been investigated. Thus, in this work, we provide evidence that, in Arabidopsis, both E2Fa and E2Fb control leaf size under UV‐B conditions without participating in the repair of cyclobutane pyrimidine dimers in the DNA. Nevertheless, in UV‐B‐exposed seedlings, E2Fa, but not E2Fb, regulates primary root elongation, cell proliferation, and programmed cell death in the meristematic zone. Using e2fa mutants that overexpress E2Fb, we showed that the role of E2Fa in the roots could not be replaced by E2Fb. Finally, our results show that E2Fa and E2Fb differentially regulate the expression of genes that activate the DNA damage response and cell cycle progression, both under conditions without UV‐B and after exposure. Overall, we showed that both E2Fa and E2Fb have different and non‐redundant roles in developmental and DNA damage responses in Arabidopsis plants exposed to UV‐B.

Morphological, Histological, and Transcriptome Analysis of Doubled Haploid Plants in Poplars (Populus simonii × Populus nigra)

“…It showed that 10 DEGs related to the growth and development of meristem (apical bud and root), which has been proven by cumulative previous research. Under the influence of ABA, the expression of PsnMYB73/77 and PsnE2F [29] were suppressed, while that of PsnHFR1/DELLA and PsnRGA/DELLA increased, which inhibited the synthesis of auxin, further inhibiting the growth of roots and buds. The upregulation of PsnSCL23 [30] affected the development of germinal layers of roots and buds.…”

Distinctive and complementary roles of E2F transcription factors during plant replication stress responses

“…Finally, because hindrance of fork progression is inevitable during the S-phase, we investigated whether E2F deficiency may trigger replication stress even in a wild-type background. Indeed, e2fa-2 e2fb-1 double mutants (but not the single mutants) have been shown to display reduced root meristem size and a global slight reduction in cell proliferation (Gómez et al, 2022) (Supplemental Figure S8). Although this phenotype could be due to the role of E2Fs as activators of cell cycle progression, it may also reflect an inefficient response to basal levels of replication stress that generally happen during the S-phase.…”

Comprehensive identification of maize ZmE2F transcription factors and the positive role of ZmE2F6 in response to drought stress

“…In eukaryotes, the ZmE2F family is characterized as a TF that plays crucial roles in cell division, DNA repair, and differentiation [ 11 , 13 – 16 ]. However, the E2F family is only genome-wide identified in a few plants, including Arabidopsis , rice, wheat, Moso bamboo, Medicago truncatula , and Phaseolus vulgaris [ 9 , 24 – 26 ].…”

“…In higher plants, E2Fs are also categorized into three subclades, including E2F, DP, and DEL (DP-E2F-like), due to the difference in the composition of conserved domains [ 9 , 10 ]. Over the past decade, E2Fs have well been revealed to play significant roles in the cell cycle and DNA damage repair [ 11 – 16 ]. For instance, ectopic expression of DcE2F1 of Daucus carota promotes cell proliferation in Arabidopsis seedlings [ 14 ].…”

“…In Arabidopsis , eight E2F members exhibit antagonistic roles in cell proliferation, such as E2Fa/b, which acts as a positive regulator, but E2Fc is a negative regulator [ 17 – 19 ]. E2Fa/b can also activate the DNA damage response and cell cycle progression by differentially regulating the expression of genes [ 11 ]. Additionally, AtE2Fa/DPa also inhibits growth, and AtE2Fa/DPa -overexpressing plants show an abnormal phenotype owing to ectopic cell division or enhanced DNA endoreduplication [ 12 , 20 ].…”