The mRNA coding for Xenopus glutamate receptor interacting protein 2 (XGRIP2) is maternally transcribed, transported through the late pathway and localized to the germ plasm

Using a large-scale in situ hybridization screening, we found that the mRNA coding for Xenopus glutamate receptor interacting protein 2 (XGRIP2) was localized to the germ plasm of Xenopus laevis. The mRNA is maternally transcribed in oocytes and, during maturation, transported to the vegetal germ plasm through the late pathway where VegT and Vg1 mRNAs are transported. In the 3'-untranslated region (UTR) of the mRNA, there are clusters of E2 and VM1 localization motifs that were reported to exist in the mRNAs classified as the late pathway group. With in situ hybridization to the sections of embryos, the signal could be detected in the cytoplasm of migrating presumptive primordial germ cells (pPGCs) until stage 35. At stage 40, when the cells cease to migrate and reach the dorsal mesentery, the signal disappeared. A possible role of XGRIP2 in pPGCs of Xenopus will be discussed.