Characterization of TRF-like genes in Arabidopsis

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

The overall goal of this project is to elucidate the architecture of telomeres in the model plant, Arabidopsis thaliana. Telomeres are essential and complex nucleoprotein structures that form protective caps on the physical ends of linear eukaryotic chromosomes. Previous studies by the Shippen lab indicate that Arabidopsis has remarkably plastic development and tolerance to genome perturbations allowing investigations of the consequences of mutations in telomere-related genes that are lethal in other species. The specific objectives of this research focus on identification and characterization of proteins that bind double-strand telomeric DNA tracts. In humans, such proteins have been shown to regulate telomere length and protect against end-to-end chromosome fusions. In a BLAST search, the Shippen lab identified eleven genes in Arabidopsis with features similar to the human double-strand telomere proteins TRF1 and TRF2. The Arabidopsis genes were designated TRF-like (TRFL). For Objective 1, the DNA binding properties of TRFL proteins will be examined as well as their interactions with proteins known to associate with telomeres in other organisms. For Objective 2, the subcellular localization of TRFL proteins will be determined to ascertain whether these components co-localize with telomeric DNA in vivo. Objective 3 will examine the function of TRFL genes in telomere length maintenance and genome stability by studying the consequences of their inactivation in mutants. For Objective 4, regulation and function of TRFL-4 will be undertaken. TRFL-4 is a novel gene whose expression is controlled by alternative mRNA splicing and leads to developmentally regulated interactions with telomeric DNA. Because telomeres and their associated proteins are conserved across evolution, these studies may provide insight into fundamental mechanisms that contribute to genome stability for a broad range of eukaryotic organisms. The project will also give students, both undergraduate and graduate, the opportunity to gain valuable expertise in plant molecular biology, cytogenetics, and biochemistry, while working at the cutting edge of genome research.