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Huggins HP, Subash JS, Stoffel H, Henderson MA, Hoffman JL, Buckner DS, Sengupta MS, Boag PR, Lee MH, Keiper BD. Distinct roles of two eIF4E isoforms in the germline of Caenorhabditis elegans. J Cell Sci 2020; 133:jcs237990. [PMID: 32079657 PMCID: PMC7132772 DOI: 10.1242/jcs.237990] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/10/2020] [Indexed: 01/15/2023] Open
Abstract
Germ cells use both positive and negative mRNA translational control to regulate gene expression that drives their differentiation into gametes. mRNA translational control is mediated by RNA-binding proteins, miRNAs and translation initiation factors. We have uncovered the discrete roles of two translation initiation factor eIF4E isoforms (IFE-1, IFE-3) that bind 7-methylguanosine (m7G) mRNA caps during Caenorhabditiselegans germline development. IFE-3 plays important roles in germline sex determination (GSD), where it promotes oocyte cell fate and is dispensable for spermatogenesis. IFE-3 is expressed throughout the germline and localizes to germ granules, but is distinct from IFE-1 and PGL-1, and facilitates oocyte growth and viability. This contrasts with the robust expression in spermatocytes of IFE-1, the isoform that resides within P granules in spermatocytes and oocytes, and promotes late spermatogenesis. Each eIF4E is localized by its cognate eIF4E-binding protein (IFE-1:PGL-1 and IFE-3:IFET-1). IFE-3 and IFET-1 regulate translation of several GSD mRNAs, but not those under control of IFE-1. Distinct mutant phenotypes, in vivo localization and differential mRNA translation suggest independent dormant and active periods for each eIF4E isoform in the germline.
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Affiliation(s)
- Hayden P Huggins
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Jacob S Subash
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Hamilton Stoffel
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Melissa A Henderson
- Department of Molecular Sciences, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, TN 37752, USA
| | - Jenna L Hoffman
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - David S Buckner
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Madhu S Sengupta
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Peter R Boag
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Myon-Hee Lee
- Department of Internal Medicine, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Brett D Keiper
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
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Abstract
1. Urinary prostaglandins (PG), kallikrein and plasma renin activity (PRA) were measured in 35 patients with essential hypertension and 22 normotensive controls before and 15 min after frusemide (40 mg intravenously). 2. PGE2 and kallikrein excretion rates were lower in hypertensive subjects, and failed to rise to the same extent after frusemide. PGF2 alpha excretion was not significantly different in the two groups of patients either before or after frusemide. PRA rose less in the hypertensive subjects after frusemide. 3. These findings support the view that there is an abnormality of renal vasodilator systems (PGE2 and kallikrein) in essential hypertension.
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