Fig. 1. Molecular analysis of vls. (A) Location of three EMS mutations in vls. All mutations lead to a premature stop codon. WD repeats are shown in grey. (B) The vls transcript and restriction map of the genomic DNA used for generating a vls rescue transgene. Exons are drawn as boxes and the putative open reading frame is indicated in black. B, BamHI; Bs, BstEII; P, PstI; R, EcoRI. (C) Expression of the P[HA-Vls] transgene in ovaries revealed by western blotting using anti-HA antibodies. A band of 50 kDa is detected in transgenic but not in wild-type ovaries. (D) Alignment of the amino acid sequences of Vls and homologous proteins: CP8824, an incomplete Anopheles gambiae homolog; human MEP50; and MGC65780 a zebrafish protein. These proteins display strong conservation of the WD repeats (grey boxes). MEP50 and the zebrafish homolog display six potential WD repeats, whereas Drosophila Vls contains only four such repeats, as predicted by the Protein Sequence Analysis server of the BioMolecular Engineering Research Center of Boston University (http://bmerc-www.bu.edu/psa/). Multiple sequence alignment of Vls and related proteins was performed using the Pileup program of the Wisconsin Package (Genetics Computer Group). Gaps in the amino acid sequence, indicated by dots, were introduced for optimal alignment. The GenBank accession numbers of these sequences are the following: CP8824_AG, EAA14269 MEP50_HS, AAL79917 MGC65780_DR, AAH56278