AtTZF gene family localizes to cytoplasmic foci.

In eukaryotes, mRNA turnover and translational repression represent important regulatory steps in gene expression. Curiously, when under cellular stresses, factors involved in these processes aggregate into cytoplasmic foci known as Processing bodies (P-bodies) and Stress Granules (SGs). In animals, CCCH Tandem Zinc Finger (TZF) proteins play important roles in mRNA decay within P-bodies. TTP, a P-body localized mammalian TZF, can bind to the 3'UTRs of mRNAs containing AU-rich elements (AREs) and recruit and activate RNA decay machineries. In plants, the function of CCCH TZF proteins is still unclear. We previously showed that AtTZF1, a member of the Arabidopsis CCCH TZF protein family, could bind both RNA and DNA in vitro, traffic between the nucleus and cytoplasmic foci, and co-localize with P-body markers AGO1, DCP2 and XRN4. In this report, we show that the other 10 members of the AtTZF gene family can similarly localize in cytoplasmic foci. Together these 11 genes, though similar in TZF sequence and sub-cellular localization, appear to be differentially expressed in response to developmental and environmental cues. We propose that AtTZF1 and its gene family members may each play distinct roles at different developmental stages and environmental conditions.