FUNCTIONAL ANALYSIS OF TAF13 IN ARABIDOPSIS THALIANA AND ITS USE FOR BIOTECHNOLOGICAL APPLICATIONS

The first step of transcription initiation is the formation of the pre-initiation complex (PIC) composed of the RNA polymerase II and several general transcription factors (GTFs)like TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH. One of the first actors in PIC assembly is TFIID that plays an important role in the recognition of the core promoter elements and is composed by the TATA-box Binding Protein (TBP) and several TBP-Associated Factors (TAFs). Considering the importance of TAFs for transcriptional regulation these genes resulted essential in all the studied model organisms. For this characteristic we selected TAFs to develop a transgene containment strategy and we functionally characterized one of the selected TAFs, TAF13, in Arabidopsis thaliana. One of the major concerns regarding the introduction of genetically modified (GM) crops is gene flow, the spreading of transgenes in the environment via pollen or seed dispersion. Male sterility represents a possible solution to this problem and in this work we report a strategy that uses recoverable inactivation of TAF activity during pollen development. The presented system has to be considered as a proof of concept in eggplant where in combination with parthenocarpy we obtained complete gene flow containment. The selected TAFs used for the transgene containment strategy are TAF13 and TAF10, the latter already characterized in Arabidopsis. I present the study of a taf13 TDNA knock-out mutant that revealed an essential role of this gene during seed development. Phenotypic similarities in endosperm over-proliferation with PRC2 mutants suggest a relationship between TAF13 and Polycomb group (PcG) proteins that are components of a repressive complex. The interaction of TAF13 with MEDEA and SWINGER, two PcG proteins, further confirmed this idea.