RT Journal Article
SR Electronic
T1 The key protein of endosomal mRNP transport binds translational landmark sites of cargo mRNAs
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 418079
DO 10.1101/418079
A1 Lilli Olgeiser
A1 Carl Haag
A1 Susan Boerner
A1 Jernej Ule
A1 Anke Busch
A1 Julian König
A1 Michael Feldbrügge
A1 Kathi Zarnack
YR 2018
UL http://biorxiv.org/content/early/2018/09/14/418079.abstract
AB RNA-binding proteins (RBPs) determine spatiotemporal gene expression by mediating active transport and local translation of cargo mRNAs. Here, we cast a transcriptome-wide view on the transported mRNAs and cognate RBP binding sites during endosomal messenger ribonucleoprotein (mRNP) transport in Ustilago maydis. Using individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP), we compare the key transport RBP Rrm4 and the newly identified endosomal mRNP component Grp1 that is crucial to coordinate hyphal growth. Both RBPs bind predominantly in the 3’ untranslated region of thousands of shared cargo mRNAs, often in close proximity. Intriguingly, Rrm4 specifically recognises landmark sites of translation, including precise binding of start and stop codons, suggesting an intimate connection of mRNA transport and translation. Towards uncovering the code of recognition, we identify UAUG as specific binding motif of Rrm4 that is bound by its third RRM domain. Altogether, we provide first insights into the positional organisation of co-localising RBPs on individual cargo mRNAs.