RNA-binding protein involved in regulation of mRNA stability (PubMed:31743541). Promotes mRNA stabilization by recruiting MKT1 and PBP1 (By similarity). Stabilizes mRNA required for differentiation from the bloodstream form to the procyclic form, and maintenance of the procyclic form (PubMed:31743541). Stabilizes transcripts encoding membrane and mitochondrial proteins, including AQP1 and GPEET2 procyclin (PubMed:31743541). Interacts (via MKT1-binding motif) with MKT1. Expressed at low levels in the bloodstream form (at protein level) (PubMed:31743541, PubMed:32532821). Expressed in the procyclic form (PubMed:31743541). Induced during differentiation of bloodstream form to procyclic form. RNAi-mediated knockdown causes abnormal differentiation of the bloodstream form into the procyclic form, a reduction in the expression of several mRNA including differentiation protein PAD1, and premature death (PubMed:31743541). RNAi-mediated knockdown at the procyclic stage causes a decrease in growth rate (PubMed:31743541). Simultaneous RNAi-mediated knockdown of ZC3H20 and ZC3H21 at the bloodstream stage is lethal (PubMed:31743541). Simultaneous RNAi-mediated knockdown of ZC3H20 and ZC3H21 at the procyclic stage causes a severe growth defect and a shift towards a bloodstream form (PubMed:31743541).