RNA-binding protein involved in regulation of mRNA stability (PubMed:31743541). Promotes mRNA stabilization by recruiting MKT1 and PBP1 (By similarity). Stabilizes transcripts encoding mitochondrial proteins (PubMed:31743541). Expressed in the procyclic form. Induced during the differentiation of the bloodstream form to the procyclic form. RNAi-mediated knockdown in procyclic form does not affect growth rate (PubMed:31743541). Simultaneous knockdown of ZC3H20 and ZC3H21 in the procyclic form results in a severe population growth defect and a shift towards the bloodstream form transcriptome (PubMed:31743541). Simultaneous knockdown of ZC3H20 and ZC3H21 in the bloodstream form is lethal (PubMed:31743541).