By excision of a P element insertion in the 5-prime UTR of the Drosophila maelstrom gene, Findley et al. (2003) isolated mael(M391), a allele of Drosophila maelstrom. They used database analysis to identify the human MAEL homolog. Confocal microscopy localized Drosophila maelstrom primarily to nuage, highly abundant particles within germline cells, and also to the nucleus and cytoplasm of germline cells. Nuclear shuttling assays showed that Drosophila maelstrom is transported between the cytoplasm and nucleus.By phenotypic characterization of Drosophila maelstrom mutants, which displayed axial patterning defects and other polarity defects, Findley et al. (2004) defined maelstrom as a spindle-class gene that affects Vasa modification.