Core components of endosomal mRNA transport are evolutionarily conserved in fungi

Abstract

Active movement of mRNAs by sophisticated transport machineries determines precise spatiotemporal expression of encoded proteins. A prominent example discovered in fungi is microtubule-dependent transport via endosomes. This mode of transport was thought to be only operational in the basidiomycete Ustilago maydis. Here, we report that distinct core components are evolutionarily conserved in fungal species of distantly related phyla like Mucoromycota. Interestingly, orthologues of the key RNA-binding protein Rrm4 from the higher basidiomycete Coprinopsis cinerea and the mucoromycete Rhizophagus irregularis shuttle on endosomes in hyphae of U. maydis. Thus, endosomal mRNA transport appears to be more wide-spread than initially anticipated.\n\nHighlights- Core transport components Upa1 and Rrm4 are conserved in different fungal phyla\n- Components of the Rrm4 machinery were most likely secondarily lost in ascomycetes\n- Upa1 from Microbotryum lychnidis-dioicae is functional in U. maydis\n- Rrm4 orthologues from Basidio- and Mucoromycota shuttle in hyphae of U. maydis