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XB-ART-42577
Mech Dev January 1, 2011; 128 (1-2): 153-63.

Nanos1 functions as a translational repressor in the Xenopus germline.

Lai F , Zhou Y , Luo X , Fox J , King ML .


Abstract
Nanos family members have been shown to act as translational repressors in the Drosophila and Caenorhabditis elegans germline, but direct evidence is missing for a similar function in vertebrates. Using a tethered function assay, we show that Xenopus Nanos1 is a translational repressor and that association with the RNA is required for this repression. We identified a 14 amino acid region within the N-terminal domain of Nanos1 that is conserved in organisms as diverse as sponge and Human. The region is found in all vertebrates but notably lacking in Drosophila and C. elegans. Deletion and substitution analysis revealed that this conserved region was required for Nanos1 repressive activity. Consistent with this observation, deletion of this region was sufficient to prevent abnormal development that results from ectopic expression of Nanos1 in oocytes. Although Nanos1 can repress capped and polyadenylated RNAs, Nanos1 mediated repression did not require the targeted RNA to have a cap or to be polyadenylated. These results suggest that Nanos1 is capable of repressing translation by several different mechanisms. We found that Nanos1, like Drosophila Nanos, associates with cyclin B1 RNA in vivo indicating that some Nanos targets may be evolutionarily conserved. Nanos1 protein was detected and thus available to repress mRNAs while PGCs were in the endoderm, but was not observed in PGCs after this stage.

PubMed ID: 21195170
PMC ID: PMC3065925
Article link: Mech Dev
Grant support: [+]
Genes referenced: ccnb1 h4c1 h4c4 myc nanos1 pgat piwil1
Antibodies: Nanos1 Ab1


Article Images: [+] show captions
References [+] :
Asaoka, Maternal Nanos regulates zygotic gene expression in germline progenitors of Drosophila melanogaster. 1999, Pubmed


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