In Metazoans, germ cell specification is critical for establishing the germline lineage. For acquiring germline identity, cells can recruit germline determinants from maternal germ plasm, typically preformed in an uncellularised egg chamber, or receive signals from neighbouring cells to induce the expression of germline genes. Since Vasa was first identified as a component of the germ plasm in the fruit fly Drosophila melanogaster about 30 years ago it has been clear that the vasa gene and its products are conserved germline markers across the animal phyla. Nonetheless, how the sequence of vasa relates to the development of germ cells remains largely unknown. This finding unveils a novel role of HELICc in addition to its well-known helicase function to localized Vasa to the germ plasm in Drosophila. By contrast, the divergent N-terminal sequences were not decisive to the germ plasm localization of Vasa though they were involved in the formation of pole cells and abdominal segments. Accordingly, we have greatly advanced the understanding about the connections between sequences and functions of Vasa using evo-devo and genetic approaches. Moreover, our findings shed light on how Vasa can act as a versatile germline marker.
