Ensures the proper localization of the mRNA of the bicoid gene to the anterior regions of the oocyte thus playing a fundamental role in the establishment of the polarity of the oocyte. May bind the bcd mRNA. Component of the osk RNP complex, which is composed of at least exuperantia (exu), ypsilon schachtel (yps), aret (bruno), cup, and the mRNA of osk (PubMed:10662770). In the sponge body, forms a ribonucleoprotein complex (RNP) containing at least me31B, exu, yps and the mRNA of osk; interactions with exu and yps are RNA dependent (PubMed:11546740). Expressed in stage 6 egg chambers.