"Functional characterization of the HUA2 gene family in Arabidopsis thaliana" by Preetam Janakirama
Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Biology

Supervisor

Dr. Vojislava Grbic

Abstract

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.

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