Transposable elements (TEs) are mobile genetic elements present in virtually all genomes. They make up nearly half of the total amount of DNA in plant genomes, so definition of their influence on genome structure and gene expression is of clear significance to the understanding of global genome regulation and phenotype variations. The movement of TEs within genomes can generate mutations by interrupting or modifying the regulation or the coding capacity of genes, and recombination between transposon copies located at different chromosomal regions can generate chromosomal rearrangements. Work done over the last few years has confirmed that TEs are at the origin of an important number of genes and regulatory sequences and that transposition has been essential for the evolution of complex genomes. They also have an important role in chromatin structure and function. Miniature Inverted Repeat Transposable Elements (MITEs) constitute a particular type of mobile elements that are present in high copy numbers in genomes. The objective of the project is to study the impact of MITEs in the regulation of nearby genes and to analyze their possible role as genome organizer elements. To this end, we will start applying dedicated bioinformatic tools to complete the Arabidopsis MITE landscape, and we will analyze the epigenetic marks associated to these elements. In a second stage of the project we will analyze their influence on the expression of neighboring genes taking advantage of the variability of MITE insertions in different Arabidopsis ecotypes. Finally, we will analyze the possible role of selected MITE families as genome organizers, by studying their localization in chromosomes by fluorescent in situ hybridization (FISH) analysis and by chromosome conformation capture approaches. In conclusion, this project constitutes an exciting combination of bioinformatics and cellular and molecular biology approaches for the analysis of genome structure and regulation via TEs.