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Updated: Jul 5, 2026
Assessment of de novo Protein Synthesis Rates in Caenorhabditis elegans
Published on: September 12, 2020
Depletion of the cap-associated isoform of translation factor eIF4G induces germline apoptosis in C. elegans
V Contreras1, M A Richardson, E Hao
1Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA.
Abstract:
During mammalian programmed cell death, cleavage of the translation initiation factor 4G proteins (eIF4GI and eIF4GII) by caspase-3 induces the cap-independent synthesis of pro-apoptotic proteins. Apoptosis occurs naturally in the gonad to remove germ cells that are not selected to grow as oocytes and mature into eggs. Here, we describe two major isoforms of Caenorhabditis elegans eIF4G that are derived from a single gene (ifg-1) and their separate roles in germline homeostasis. Full length IFG-1 protein (170 kDa isoform) differs from the shorter isoform (130 kDa) by the inclusion of the N-terminal domain containing the putative eIF4E-binding site required for mRNA cap recognition. Depletion of the cap-associated p170 isoform induced CED-4 expression in oocytes and markedly increased germline apoptotic events, but did not prevent early mitotic germ cell proliferation. Loss of both p170 and p130 suppressed germ cell proliferation and arrested larval development. Evidence suggests that eIF4G isoforms are differentially utilized during oogenesis to regulate germ cell apoptosis. We propose that an alternative mechanism to eIF4G cleavage may be employed in germ cells by changing the availability of the p170 isoform.
Insights
Two Caenorhabditis elegans eIF4G isoforms regulate germ cell apoptosis during oogenesis. Depleting the p170 isoform increases germ cell death, suggesting differential utilization for apoptosis regulation.
Area of Science:
- Cell Biology
- Developmental Biology
- Genetics
Background:
- Programmed cell death (apoptosis) is crucial for development and homeostasis.
- In mammals, caspase-3 cleavage of translation initiation factor 4G (eIF4G) promotes apoptosis.
- Germ cell apoptosis naturally occurs in the gonad to eliminate non-selected cells.
Purpose of the Study:
- To investigate the roles of Caenorhabditis elegans eIF4G isoforms in germline homeostasis.
- To understand how eIF4G isoforms regulate germ cell apoptosis during oogenesis.
Main Methods:
- Characterization of two major eIF4G isoforms (p170 and p130) from the C. elegans ifg-1 gene.
- Depletion studies using RNA interference to assess isoform-specific functions.
- Analysis of germ cell proliferation and apoptosis.
Main Results:
- Depletion of the cap-associated p170 isoform increased germ cell apoptosis by inducing CED-4 expression in oocytes.
- Loss of both p170 and p130 isoforms suppressed germ cell proliferation and arrested larval development.
- Evidence suggests differential utilization of eIF4G isoforms in regulating germ cell apoptosis.
Conclusions:
- Caenorhabditis elegans eIF4G isoforms play distinct roles in germline homeostasis and apoptosis.
- The availability of the p170 isoform may be regulated to control germ cell apoptosis, potentially via an alternative mechanism to eIF4G cleavage.
