Figure 3.

Activators of deadenylation promote rapid mRNA decay. Both CELF1/EDEN-BP and ZFP36 proteins promote deadenylation-dependent decay by binding 3’UTRs of target transcripts and recruiting deadenylation factors. CELF1/EDEN-BP has been shown to directly bind transcript 3’UTRs and recruit the polyA ribonuclease (PARN) to promote rapid transcript deadenylation in Xenopus embryos. Additionally, ZFP36 proteins bind AU-rich elements within transcript 3’UTRs and promote deadenylation through recruitment of PARN or the CCR4-NOT complex via CNOT9. Both RNA binding proteins have been shown to regulate segmentation clock transcript stability, and further biochemical evidence will determine whether these precise interactions are also important in the context of segmentation clock transcript deadenylation and decay.