An eIF4E-binding protein regulates katanin protein levels in C. elegans embryos.
In Caenorhabditis elegans, the MEI-1-katanin microtubule-severing complex is required for meiosis, but must be down-regulated during the transition to embryogenesis to prevent defects in mitosis. A cullin-dependent degradation pathway for MEI-1 protein has been well documented. In this paper, we report that translational repression may also play a role in MEI-1 down-regulation. Reduction of spn-2 function results in spindle orientation defects due to ectopic MEI-1 expression during embryonic mitosis. MEL-26, which is both required for MEI-1 degradation and is itself a target of the cullin degradation pathway, is present at normal levels in spn-2 mutant embryos, suggesting that the degradation pathway is functional. Cloning of spn-2 reveals that it encodes an eIF4E-binding protein that localizes to the cytoplasm and to ribonucleoprotein particles called P granules. SPN-2 binds to the RNA-binding protein OMA-1, which in turn binds to the mei-1 3' untranslated region. Thus, our results suggest that SPN-2 functions as an eIF4E-binding protein to negatively regulate translation of mei-1.
Li
Wei
W
Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
DeBella
Leah R
LR
Guven-Ozkan
Tugba
T
Lin
Rueyling
R
Rose
Lesilee S
LS
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000502:physiology; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D000074201:Katanin; D011485:Protein Binding / Q000235:genetics; D012261:Ribonucleoproteins / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D039561:Eukaryotic Initiation Factor-4E; D012261:Ribonucleoproteins; D000251:Adenosine Triphosphatases; D000074201:Katanin