RNA-Seq analysis of wild-type and ttpA-D450trx mutant D. discoideum amebae

In many eukaryotes, mRNAs containing specific AU-rich motifs are regulated by proteins of the tristetraprolin (TTP) family, which bind to these motifs through a tandem zinc finger (TZF) domain. This binding leads to promotion of subsequent deadenylation and decay, partly through a conserved carboxyl-terminal CNOT1 binding domain. We explored the physiological role of the single TTP family member (TtpA) expressed in Dictyostelium discoideum. This study shows the effect of a carboxyl-terminal truncation (ttpA-D450trx), which removed the predicted CNOT1 binding domain, evaluated in amebae in growth medium during surface culture. The cells exhibited external and gene expression phenotypes that were very similar to those of two distinct null mutants, raising the possibility that this domain is necessary for TtpA-promoted mRNA decay in this species. Overall design: Dictyostelium discoideum amebae (strain AX3) were grown in normal growth medium under axenic conditions in plastic flasks until they were approximately 80% confluent. Four cultures of wild-type cells and four cultures of ttpA-D450trx cells were then frozen and used for RNA extraction and RNA-Seq analysis.