HAG3, a Histone Acetyltransferase, Affects UV-B Responses by Negatively Regulating the Expression of DNA Repair Enzymes and Sunscreen Content in Arabidopsis thaliana

JULIETA FINA; PAULA CASATI

PLANT AND CELL PHYSIOLOGY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2015 vol. 56 p. 1388 - 1400

0032-0781

Histone acetylation is regulated by histone acetyltransferases and deacetylases. In Arabidopsis, there are 12 histone acetyltransferases and 18 deacetylases, histone acetyltransferases are organized in 4 families: the GNAT/HAG, the MYST, the p300/CBP and the TAFII250 families. Previously, we demonstrated that Arabidopsis mutants in the two members of the MYST acetyltransferase family show increased DNA damage after UV-B irradiation. To further investigate the role of other histone acetyltransferases in UV-B responses, a putative role of enzymes of the GNAT family, HAG1, HAG2 and HAG3, was analyzed. HAG transcripts are not UV-B regulated; however, hag3 RNAi transgenic plants show a lower inhibition of leaf and root growth by UV-B, higher levels of UV-B absorbing compounds and less UV-B induced DNA damage than Ws plants, while hag1 RNAi transgenic plants and hag2 mutants do not show significant differences with WT plants. Transcripts for UV-B regulated genes are highly expressed under control conditions in the absence of UV-B in hag3 RNAi transgenic plants, suggesting that the higher UV-B tolerance may be due to increased levels proteins that participate in UV-B responses. Together, our data provide evidence that HAG3, directly or indirectly, participate in UV-B induced-DNA damage repair and signaling.