Ph.D. Exit Seminar - Srimathi Bogamuwa

Nov 18, 2014, 9:00am - 10:00am
Deadline: 
Srimathi Bogamuwa, Ph.D. Student

Advisor: Dr. J. C. Jang
Committee: Dr. Michelle Jones, Dr. Pablo Jourdan, Dr. Randall Scholl

Tuesday November 18th, 2014
9.00 AM – 10.00 AM



102, (CAPS conference room) Rightmire Hall (Columbus)
video linked to
123 Williams (Wooster)

Functional Characterization of Three Seed-Specific Tandem CCCH Zinc Finger Proteins in Arabidopsis thaliana


Abstract

Mammalian Tandem CCCH Zinc Finger proteins (TZFs) are potent regulators of gene expressions by recruiting catabolism machineries to degrade specific mRNAs. This regulation takes place in Processing-bodies (P-bodies, PBs) and stress granules (SGs) that are cytoplasmic aggregations of messenger ribonucleoprotein (mRNP) complexes formed during translational repression. Unlike in mammals, plant TZF proteins are over-represented by members containing a unique TZF domain preceded by an arginine (R)-rich (RR) motif called RR-TZF. I have performed functional characterization of three seed-specific Arabidopsis RR-TZF genes, AtTZF4, AtTZF5 and AtTZF6 in this study. Mutant analyses indicate that AtTZF4, 5 and 6 act as positive regulators for ABA- and negative regulators for light- and GA-mediated seed germination responses. Further analyses reveal that AtTZF4, 5 and 6 affect seed germination by controlling genes critical for ABA and GA accumulation and response. Moreover, AtTZF4, 5 and 6 can co-localize with both PB and SG markers in plant cells. Yeast two-hybrid library screening reveal that AtTZF4, 5 and 6 preferentially interact with stress responsive proteins. Results of additional biochemical and imaging analyses indicate that TZF domain is sufficient for AtTZF5 to interact with two stress response regulators. In summary, my research has revealed novel insights into the roles of RR-TZF proteins in hormone-mediated plant growth, stress, and gene expression responses.