Electronic Thesis and Dissertation Repository


Doctor of Philosophy




Dr. Vojislava Grbic


HUA2 encodes a key developmental regulatory protein implicated in the coordination of induction and the maintenance of floral state in Arabidopsis. To gain further insight into the function of HUA2, I have conducted a series of studies aimed at elucidating the molecular function(s) of its individual domains. I show that the PWWP, RPR and CT-proline rich domains within HUA2 are required for the proper regulation of the flowering time phenotype. I also establish that HUA2 interacts with characterized splicing factors (FCA, AtPRP40, RBP45 and UBP1) through its CT-proline rich domain. In addition, I examine the overlap in function between HUA2 and its related family members (the HUA2-like genes, HULK1, HULK2 and HULK3). I show that all members of the family localize to the nucleus where they interact with the same set of pre-mRNA processing factors (FCA, AtPRP40, RBP45 and UBP1). Lastly, I show that HUA2 interacts with the AtCTD via binding to CTD heptad repeats that are phosphorylated exclusively on Ser-2 residues. This key result is consistent with my data demonstrating the interaction of HUA2 with splicing factors, and strongly suggests a role for HUA2 in the 3’-end processing of pre-mRNAs. The possible involvement of HUA2 in regulating the pre-mRNA processing of genes involved in floral development is discussed.