A novel null allele of mouse DSCAM survives to adulthood on an inbred C3H background with reduced phenotypic variability.

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Animals, Base-Pairing, Cell-Adhesion-Molecules, Exons, Frameshift-Mutation, Homozygote, Mice, Mice-Inbred-C3H, Mice-Knockout, Mutation, Neurites, Phenotype, Retina

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Genesis 2010 Oct; 48(10):578-84.


DSCAMs are cell adhesion molecules that play several important roles in neurodevelopment. Mouse alleles of Dscam identified to date do not survive on an inbred C57BL/6 background, complicating analysis of DSCAM-dependent developmental processes because of phenotypic variability related to the segregating backgrounds needed for postnatal survival. A novel spontaneous allele of Dscam, hereafter referred to as Dscam(2)(J), has been identified. This allele contains a four base pair duplication in exon 19, leading to a frameshift and truncation of the open reading frame. Mice homozygous for the Dscam(2)(J) mutant allele survive into adulthood on the C3H/HeJ background on which the mutation was identified. Using the Dscam(2)(J) allele, retinal phenotypes that have variable severity on a segregating background were examined. A neurite lamination defect similar to that described in chick was discovered in mice. These results indicate that, in the retina, additional DSCAM-dependent processes can be found by analysis of mutations on different genetic backgrounds.