Arabidopsis Mediator subunit 17 connects transcription with DNA repair after UV-B exposure

MARISOL GIUSTOZZI; SANTIAGO NICOLÁS FREYTES; AIME JASKOLOWSKI; MICAELA LICHY; JULIETA L. MATEOS; MARÍA LORENA FALCONE FERREYRA; GERMÁN L. ROSANO; PABLO CERDÁN; PAULA CASATI

PLANT JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2022

0960-7412

Mediator 17 (MED17) is a subunit of the Mediator complex that regulates transcription initiation in eukaryotic organisms. In yeast and humans, MED17 also participates in DNA repair, physically interacting with proteins of the Nucleotide Excision DNA Repair system, but this function in plants has not been investigated. We studied the role of MED17 in Arabidopsis plants exposed to UV-B radiation. Our results demonstrate that med17 and OE MED17 plants have altered responses to UV-B; and that MED17 participates in various aspects of the DNA damage response (DDR). Comparison of med17 transcriptome to that of WT plants showed that almost one third of transcripts with altered expression in med17 plants were also changed by UV-B exposure in WT plants. Increased sensitivity to DNA damage after UV-B in med17 plants can be due to altered regulation of UV-B responsive transcripts; but additionally, MED17 physically interacts with DNA repair proteins, suggesting a direct role of this Mediator subunit during repair. Finally, we show that MED17 is necessary to regulate the DDR activated by ATR, and that PDCD5 overexpression reverts the deficiencies in DDR shown in med17 mutants. Our data demonstrates that MED17 is an important regulator of the DDR after UV‐B irradiation in Arabidopsis.