Figure 1.—

mus309 alleles. Boxes indicate exons; untranslated regions are hatched (only the beginning of the 3′-UTR is shown) and the region encoding the RecQ core is shaded. Vertical lines mark the positions of the seven conserved motifs of superfamily II helicases. The insertion site of the P{EPgy2}mus309^EY03745 element used to generate deletions is indicated by a solid triangle. The positions of the nonsense mutation in mus309^D2 and the missense mutation in mus309^D3 are given above the schematic, and the regions deleted in mus309^N alleles are indicated below with dashed lines.