M. Naydenov*, B. Georgieva, V. Baev, G. Yahubyan
Department of Plant Physiology and Molecular Biology, University of Plovdiv, 24 Tsar Assen, 4000 Plovdiv, Bulgaria
Abstract. Unlike prokaryotic DNA, eukaryotic DNA is packed in a chromatin with a number of proteins, of which histones are the most important for chromatin structure and dynamics. Along with the 5 canonical histones- H2A, H2B, H3, H4 and H1 linker histone, there are many histone variants. The latter proteins play a crucial role in chromatin remodeling and gene regulation. Studies investigating the involvement of the H3 variant – H3.3 in later developmental stages and stress response of plant are few. In this work we searched available databases for histone variants of A. thaliana and 54 genes coding histones in A. thaliana were identified, 14 of them belonged to the H3 family. In order to analyze this family, multiple alignments of the corresponding amino acid sequences were performed. The gene AT4G40030 which encodes H3.3 showed 3 transcriptional variants. The expression analysis revealed that the two of variants – H3.3 (1) and H3.3 (2) were found in all overground organs, but the third one – H3.3 (3) was not detected in any of them. Semi-quantitative PCR analysis of heat-treated plants revealed that H3.3 (1) and H3.3 (2) had a higher expression compared with untreated control. These results suggest participation of these H3.3 (1) and H3.3 (2) variants in development processes and plants response to abiotic stress.