Fig. 4. Mapping and molecular characterization of Nap1 alleles. (A) The khlo mutation mapped between the SSLP markers D2SKI308 and D2SKI324 on chromosome 2 (http://mouse.ski.mskcc.org/). (B) Alignment of the N-terminal region of murine Nap1 (Mm) and its human (Hs), Drosophila melanogaster (Dm, kette) and C. elegans (Ce, gex-3) homologs. The leucine residue mutated in Nap1^khlo is conserved in all four species (red box) and occurs in a leucine-rich region of the protein. (C,D) The Nap1^GT insertion trapped the Nap1 transcript after exon 24 (C), creating a fusion of the 898 N-terminal amino acids of Nap1 with ß-geo (D). (E,F) Nap1^khlo/Nap1^GT mutants (F) arrested at E8.5 with multiple morphogenetic defects, including a distended primitive streak (arrows) and malformed somites (arrowheads); compare with wild type (E). Anterior is to the left in E and F.