EXAMINING PROTEIN-PROTEIN INTERACTIONS AND THEIR ROLE IN THE TRANSCRIPTIONAL REGULATION OF THE FLORAL ORGANS OF ARABIDOPSIS THALIANA

In this study, the organism Arabidopsis thaliana, a known model of floral development, is used to outline the combinatorial role that multiple genes and their proteins play in the regulation and specificity of each floral organ. The ABCE homeotic floral organ identity genes are responsible for the specification of floral organ fate in each whorl of the flower. Other genes known as boundary genes are characterized to uphold the boundaries between whorls by regulating the expression of the identity genes. This study examines the boundary genes known as SUPERMAN (SUP) and RABBIT EARS (RBE) and their interactions with other proteins to achieve a mechanism of transcriptional repression resulting in proper floral organ development and patterning. We demonstrate that the corepressor TOPLESS (TPL) interacts with SUP through its EAR motif and that a fully intact EAR motif is required for this interaction to occur. Additionally, our findings suggest that this SUP-TPL interaction is responsible for upholding the boundary between whorls 3 and 4 by repressing the expression of the B-class genes AP3 and PI in the innermost whorl. Overall, this study can lead to a better understanding of how specific mechanisms of transcriptional regulation are used to maintain the function of stem cell populations for proper organ specification and development in all eukaryotes.