Fig. 2

Ly02-512 encodes an allele of polydom/svep1. A, Positional cloning approach to identify the molecular lesion in Ly02-512 mutant embryos. Using polymorphic markers, Ly02-512 was mapped to a region between markers z4.29 and z.7.4 comprising ≈350 kb on linkage group 7. B, Three different BAC constructs that were independently inserted as transgenes into the Ly02-512 line containing 12 candidate genes within the linkage group. C, In Ly02-512 mutant embryos which contained the DKEY-8E16 BAC, the TD phenotype was rescued (P<0.001), suggesting DKEY-8E16 to contain the gene of interest. D, Two other mutant lines identified in the forward genetic screen, Ly04-093 and Ly05-265, failed to complement Ly02-512 and each other, suggesting that they represent alleles of the same gene. E, Sequencing of the 3 independent mutant alleles revealed 3 different nonsense substitutions, predicted to result in truncated versions of the Polydom/Svep1 protein. F, Schematic presentation of the Polydom/Svep1 protein domain structure and the positions of the truncations in the 3 mutant lines. Red rectangle: signal peptide; blue pentagon: von Willebrand factor type A domain; yellow ovals: SUSHI repeat; green pentagons: epidermal growth factor (EGF)–like and calcium-binding EGF-like domains; and pink hexagon: pentraxin domain.