J Biol Chem
July 24, 2009;
Participation of Xenopus Elr-type proteins in vegetal mRNA localization during oogenesis.
Directional transport of specific mRNAs is of primary biological relevance. In Xenopus oocytes, mRNA localization to the vegetal pole is important for germ layer formation and germ cell development. Using a biochemical approach, we identified Xenopus Elr-type proteins, homologs of the Hu/ELAV proteins, as novel components of the vegetal mRNA localization machinery. They bind specifically to the localization elements of several different vegetally localizing Xenopus mRNAs, and they are part of one RNP together with other localization proteins, such as Vg1RBP
and XStaufen 1. Blocking Elr-type protein binding by either localization element mutagenesis or antisense morpholino oligonucleotide-mediated masking of their target RNA structures, as well as overexpression of wild type and mutant ElrB
proteins, interferes with vegetal localization in Xenopus oocytes.
J Biol Chem
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FIGURE 4. Subcellular distribution of ElrA and B in oocytes.A, co-immunostaining on cryo sections of a stage IV oocyte using α-HuR and α-XStaufen 1 antibodies. Animal (An) and vegetal (Veg) hemispheres are marked in the brightfield image (upper left). α-HuR and α-XStaufen 1 stainings are shown in red and green, respectively. Magnifications of animal and vegetal halves of the oocyte are shown below. Arrowheads mark vegetal cortex enrichment of ElrA/B and XStaufen 1, respectively. B, nuclei and cytoplasmatic fractions of stage IIII oocytes were manually dissected and ElrA/B and 40LoVe proteins detected by Western blotting. Proteins that might correspond to putative ElrB isoforms are marked by stars. C, nucleocytoplasmic transport assay with ElrA and B. 35S-Labeled, Myc-tagged versions of the proteins were injected into the cytoplasms or nuclei of stage VI oocytes. These were dissected either directly or 4 h after injection. Myc-tagged proteins were immunoprecipitated from these fractions, separated by SDS-PAGE, and detected by phosphorimaging.
This research was originally published in The Journal of Biological Chemistry. Arthur et al “Participation of Xenopus Elr-type proteins in vegetal mRNA localization during oogenesis.” July 24, 2009; 284 (30): 19982-19992. © The American Society for Biochemistry and Molecular Biology. Reproduced with permission.
Alarcón, RNA anchoring in the vegetal cortex of the Xenopus oocyte. 2001, Pubmed