The Lupus Autoantigen La Prevents Mis-channeling of tRNA Fragments into the Human MicroRNA Pathway

Daniele Hasler; Gerhard Lehmann; Yasuhiro Murakawa; Filippos Klironomos; Leonhard Jakob; Friedrich A Grässer; Nikolaus Rajewsky; Markus Landthaler; Gunter Meister

doi:10.1016/j.molcel.2016.05.026

The Lupus Autoantigen La Prevents Mis-channeling of tRNA Fragments into the Human MicroRNA Pathway

Mol Cell. 2016 Jul 7;63(1):110-24. doi: 10.1016/j.molcel.2016.05.026. Epub 2016 Jun 23.

Authors

Daniele Hasler¹, Gerhard Lehmann¹, Yasuhiro Murakawa², Filippos Klironomos³, Leonhard Jakob¹, Friedrich A Grässer⁴, Nikolaus Rajewsky³, Markus Landthaler², Gunter Meister⁵

Affiliations

¹ Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg 93053, Germany.
² Laboratory for RNA Biology and Posttranscriptional Regulation, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin 13125, Germany.
³ Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin 13125, Germany.
⁴ Institute of Virology, Saarland University Medical School, Homburg/Saar 66421, Germany.
⁵ Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg 93053, Germany. Electronic address: gunter.meister@vkl.uni-regensburg.de.

PMID: 27345152
DOI: 10.1016/j.molcel.2016.05.026

Abstract

The Lupus autoantigen La is an RNA-binding protein that stabilizes RNA polymerase III (Pol III) transcripts and supports RNA folding and has in addition been implicated in the mammalian microRNA (miRNA) pathway. Here, we have analyzed effects of La depletion on Argonaute (Ago)-bound small RNAs in human cells. We find that in the absence of La, distinct tRNA fragments are loaded into Ago proteins. Thus, La functions as gatekeeper ensuring correct tRNA maturation and protecting the miRNA pathway from potentially functional tRNA fragments. However, one specific isoleucin pre-tRNA produces both a functional tRNA and a miRNA even when La is present. We demonstrate that the fully complementary 5' leader and 3' trailer of the pre-tRNA-Ile form a double-stranded RNA molecule that has low affinity to La. Instead, Exportin-5 (Xpo5) recognizes it as miRNA precursor and transports it into the cytoplasm for Dicer processing and Ago loading.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

A549 Cells
Argonaute Proteins / metabolism
Autoantigens / genetics
Autoantigens / metabolism*
Binding Sites
DEAD-box RNA Helicases / metabolism
HEK293 Cells
HeLa Cells
Hep G2 Cells
Herpesvirus 4, Human / genetics
Herpesvirus 4, Human / metabolism
Humans
Karyopherins / metabolism
MCF-7 Cells
MicroRNAs / genetics
MicroRNAs / metabolism*
Nucleic Acid Conformation
Protein Binding
RNA Interference
RNA Polymerase III / metabolism
RNA Precursors / chemistry
RNA Precursors / genetics
RNA Precursors / metabolism*
RNA Processing, Post-Transcriptional*
RNA, Transfer, Ile / chemistry
RNA, Transfer, Ile / genetics
RNA, Transfer, Ile / metabolism*
RNA, Viral / genetics
RNA, Viral / metabolism
Ribonuclease III / metabolism
Ribonucleoproteins / genetics
Ribonucleoproteins / metabolism*
SS-B Antigen
Structure-Activity Relationship
Transfection

Substances

Argonaute Proteins
Autoantigens
Karyopherins
MicroRNAs
RNA Precursors
RNA, Transfer, Ile
RNA, Viral
Ribonucleoproteins
XPO5 protein, human
RNA Polymerase III
DICER1 protein, human
Ribonuclease III
DEAD-box RNA Helicases