MBD proteins in Arabidopsis: involvement in plant responses after irradiation with UV-B radiation

MARISOL GIUSTOZZI; JULIA I. QÜESTA; PAULA CASATI

Congreso; RAFV2020; 2021

In eukaryotes, DNA methylation is one of the most important epigenetic regulations. In particular, the modification of cytosines is related to gene silencing. In animals and plants, there are specialized methyl CPG binding domain protein (MBD) proteins that have the ability to interpret these modifications. MBD proteins act together with chromatin modifying complexes by repressing transcription, and play a biological role regulating genomic stability. In maize, MBD101 acts facilitating methyltransferase activity under stress conditions. In Arabidopsis, there are 4 proteins MBD domain proteins, which show homology to maize MBD101: MBD1, MBD2, MBD3 and MBD4.In recent years, an increase in the levels of ultraviolet B radiation reaching the earth´s surface has been measured. Plants, being sessile organisms, are exposed to ultraviolet B radiation, causing lesions in macromolecules such as proteins, DNA, RNA and lipids. Thus, the aim of this work is to investigate the function of MBD1, MBD2, MBD3 and MBD4 proteins in Arabidopsis thaliana in UV-B exposed plants. For this purpose, we analyzed mbd1, mbd2, mbd3, mbd4 mutant plants grown under UV-B conditions. Our results show that mbd1, mbd2, mbd3, mbd4 mutants show increased DNA damage after UV-B exposure. Moreover, plants with decreased levels of each of these MBD proteins showed lower programmed cell death than wild-type plants. These plants also present alterations in cell proliferation both in control and after UV-B conditions. Together, our results suggest that MBD1, MBD2, MBD3, MBD4 participate in DNA damage responses after UV-B in Arabidopsis.