Spatial and temporal translational control of germ cell mRNAs mediated by the eIF4E isoform IFE-1
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Date
2015
Authors
Friday, Andrew J.
Henderson, Melissa A.
Morrison, J. Kaitlin
Hoffman, Jenna L.
Keiper, Brett D.
Journal Title
Journal ISSN
Volume Title
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Abstract
Regulated mRNA translation is vital for germ cells to produce new
proteins in the spatial and temporal patterns that drive gamete
development. Translational control involves the de-repression of
stored mRNAs and their recruitment by eukaryotic initiation factors
(eIFs) to ribosomes. C. elegans expresses five eIF4Es (IFE-1–IFE-5);
several have been shown to selectively recruit unique pools of mRNA.
Individual IFE knockouts yield unique phenotypes due to inefficient
translation of certain mRNAs. Here, we identified mRNAs
preferentially translated through the germline-specific eIF4E isoform
IFE-1. Differential polysome microarray analysis identified 77 mRNAs
recruited by IFE-1. Among the IFE-1-dependent mRNAs are several
required for late germ cell differentiation and maturation. Polysome
association of gld-1, vab-1, vpr-1, rab-7 and rnp-3 mRNAs relies on
IFE-1. Live animal imaging showed IFE-1-dependent selectivity in
spatial and temporal translation of germline mRNAs. Altered MAPK
activation in oocytes suggests dual roles for IFE-1, both promoting
and suppressing oocyte maturation at different stages. This single
eIF4E isoform exerts positive, selective translational control during
germ cell differentiation.