Interaction of 42Sp50 with the vegetal RNA localization machinery in Xenopus laevis oocytes.
Localization of a specific subset of maternal mRNAs to the vegetal cortex of Xenopus oocytes is important for the regulation of germ layer formation and germ cell development. It is driven by vegetal localization complexes that are formed with the corresponding signal sequences in the untranslated regions of the mRNAs and with a number of different so-called localization proteins. In the context of the present study, we incorporated tagged variants of the known localization protein Vg1RBP into vegetal localization complexes by means of oocyte microinjection. Immunoprecipitation of the corresponding RNPs allowed for the identification of novel Vg1RBP-associated proteins, such as the embryonic poly(A) binding protein, the Y-box RNA-packaging protein 2B and the oocyte-specific version of the elongation factor 1α (42Sp50). Incorporation of 42Sp50 into localization RNPs could be confirmed by co-immunoprecipitation of Vg1RBP and Staufen1 with myc-tagged 42Sp50. Furthermore, myc-42Sp50 was found to co-sediment with the same two proteins in large, RNAse-sensitive complexes, as well as to associate specifically with several vegetally localizing mRNAs but not with nonlocalized control RNAs. Finally, oocyte microinjection experiments reveal that 42Sp50 is a protein that shuttles between the nucleus and cytoplasm. Taken together, these observations provide evidence for a novel function of 42Sp50 in the context of vegetal mRNA transport in Xenopus oocytes.
Department of Developmental Biochemistry, Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
Jana
J
Loeber
Maike
M
Claussen
Olaf
O
Jahn
Tomas
T
Pieler
D000818:Animals; D005260:Female; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D034443:RNA Transport; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000502:physiology*
D010445:Peptide Elongation Factors; D029867:Xenopus Proteins; C066976:thesaurin A; D012313:RNA