A novel essential RNA-binding protein complex in Trypanosoma brucei

ABSTRACT: ZC3H5 is an essential cytoplasmic trypanosome protein with a single Cx7Cx5Cx3H zinc finger domain. We here show that ZC3H5 forms a complex with three other proteins, encoded by genes Tb927.11.4900, Tb927.8.1500 and Tb927.7.3040. ZC3H5 interacts directly with Tb927.11.4900, which in turn interacts with Tb927.7.3040. Tb927.11.4900 has a circularly permuted GTPase domain, which is required for the Tb927.7.3040 interaction. RNA immunoprecipitation revealed that ZC3H5 is preferentially associated with poorly translated, low-stability mRNAs, the 5'-untranslated regions and coding regions of which were enriched in the motif (U/A)UAG(U/A). Tethering of ZC3H5, or other complex components, to a reporter repressed its expression. However, depletion of ZC3H5 in vivo did not increase the abundance of ZC3H5-bound mRNAs; instead, counter-intuitively, there were very minor decreases in a few targets. This was accompanied by marked increases in the abundance of very stable mRNAs encoding ribosomal proteins. Depletion also resulted in an increase in monosomes at the expense of large polysomes, and appearance of a "halfmer" disomes containing two 80S subunits and one 40S subunit. We speculate that the ZC3H5 complex is implicated in quality control during the translation of sub-optimal open reading frames, and that its assembly is regulated by GTP hydrolysis and GTP-GDP exchange.

INSTRUMENT(S):

ORGANISM(S): Trypanosoma Brucei

TISSUE(S): Blood Cell

DISEASE(S): Trypanosomiasis

SUBMITTER: Thomas Ruppert  

LAB HEAD: Thomas Ruppert

PROVIDER: PXD019073 | Pride | 2020-09-23

REPOSITORIES: Pride