Export of Precursor tRNAIle from the Nucleus to the Cytoplasm in Human Cells

Min Wei; Xia Zhao; Mi Liu; Meijuan Niu; Elias Seif; Lawrence Kleiman

doi:10.1371/journal.pone.0154044

Export of Precursor tRNAIle from the Nucleus to the Cytoplasm in Human Cells

PLoS One. 2016 Apr 21;11(4):e0154044. doi: 10.1371/journal.pone.0154044. eCollection 2016.

Authors

Min Wei^{1

2}, Xia Zhao², Mi Liu³, Meijuan Niu², Elias Seif², Lawrence Kleiman²

Affiliations

¹ School of Medicine, Nankai University, Tianjin, China.
² Lady Davis Institute, Jewish General Hospital, McGill University, Canada.
³ State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.

Abstract

In the current concept, tRNA maturation in vertebrate cells, including splicing of introns, trimming of 5' leader and 3' trailer, and adding of CCA, is thought to occur exclusively in the nucleus. Here we provide evidence to challenge this concept. Unspliced intron-containing precursor tRNAIle was identified in Human Immunodeficiency Virus type 1 (HIV-1) virions, which are synthesized in the cytoplasm. Northern blot, confocal microscopy and quantitative RT-PCR further verified enrichment of this unspliced tRNAIle within the cytoplasm in human cells. In addition to containing an intron, the cytoplasmic precursor tRNAIle also contains a short incompletely processed 5´ leader and a 3´ trailer, which abundance is around 1000 fold higher than the nuclear precursor tRNAIle with long 5' leader and long 3' trailer. In vitro data also suggest that the cytoplasmic unspliced end-immature precursor tRNAIle could be processed by short isoform of RNase Z, but not long isoform of RNase Z. These data suggest that precursor tRNAs could export from the nucleus to the cytoplasm in human cells, instead of be processed only in the nucleus.

Publication types

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

MeSH terms

Biological Transport
Cell Nucleus / metabolism*
Cytoplasm / metabolism*
Genes, Viral
HIV-1 / genetics
Humans
Introns
RNA Precursors / metabolism*
RNA Processing, Post-Transcriptional
RNA, Transfer, Ile / metabolism*
Reverse Transcriptase Polymerase Chain Reaction
Virion / genetics

Substances

RNA Precursors
RNA, Transfer, Ile

Grants and funding

This study is supported by the Canadian Institutes of Health Research (CIHR, HOP 81389 to L.K.), Nankai University starting fund (ZB15006101 to M. W.), and National Natural Science Foundation of China (81571991 to M. W.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.