OBJECTIVETo perform the genetic identification of cloche(172) mutant zebrafish.

METHODSThe chemical mutagen N-ethyl-N-nitrosourea (ENU) was used to treat the AB stain male fish. Large-scale forward genetic screening was carried out to search for lyC-deficient zebrafish mutant by WISH. The morphology changes of the embryos at 3 days postfertilization (3dpf) stage were observed and the cloche(172) gene was identified by mapping and complementation test.

RESULTSWe selected 4 lyC-deficient zebrafish by WISH. cloche(172) mutant showed morphological changes similar to cloche mutant in 3dpf stage. One fourth of the embryos showed cloche phenotype as found in complementation test, and the cloche(172) gene was mapped on the telomere of zebrafish 13 chromosome where cloche gene was located. Numerous red blood cells were observed in the cloche(172) mutant, while only a few cells were found in the cloche mutant in the tail region by o-dianisdine staining.

CONCLUSIONcloche(172) gene which is responsible for the phenotype of cloche mutant may be a novel point mutation allele of the cloche mutant.