ROLE OF HISTONE ACETYLATION IN THE UV-B DNA DAMAGE REPAIR IN PLANTS

MABEL CAMPI; LUCIO D´ANDREA; JULIA EMILIANI; PAULA CASATI

Tucumán

Congreso; XLV Reunión Annual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB).; 2009

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Plant development and physiology are affected by UV-B radiation. This radiation induces the formation of photoproducts in DNA (DPCs); in addition, the structural and dynamic properties of chromatin are modified by UV-B. Previous studies showed that, in maize, the acetylation of histones H3 and H4 N-terminus is increased after 8h of UV-B irradiation. Thus, we studied the role of histone acetyltransferases in the repair of the DNA damage caused by UV-B. Curcumin is an inhibitor of the activity of these enzymes. Maize leaves of the B73 genotipe were treated with curcumin prior to the UV-B treatment. Plants treated with ethanol were used as controls. After the UV-B treatment, we measured increased DPC accumulation in plants treated with curcumin in comparison with control plants. The experiment was repeated using Arabidopsis thaliana plants, including WT plants and T-DNA knockout mutants in chc1 and sdg26 genes, which encode two chromatin remodeling proteins regulated by UV-B. As for maize plants, arabidopsis DNA was more damaged in plants pretreated with curcumin than in control plants after the UV-B treatment. Moreover, sdg26 plants were more susceptible to DNA damage than WT plants; this suggests that this line has an increased UV-B sensitivity. We are now investigated he effects of UV-B radiation in arabidopsis knockout and RNAi mutants in two histone acetyltransferases, ham1 and ham2, which contain a MYST domain. The role of these proteins in DNA repair after UV-B exposure is under study.