Pax3^Sp

The mutation comprises the replacement of TCTCCA with CGTGT at the 3' end of intron 3. Since the CA dinucleotide at the end is part of the exon 4 CAG splice acceptor site, this splice site is eliminated in this allele, having been changed to GTG. This mutation abrogates the normal splicing of intron 3, resulting in the generation of four aberrantly spliced mRNA transcripts. Two of these Pax-3 transcripts make use of cryptic 3' splice sites within the downstream exon, generating small deletions which disrupt the reading frame of the transcripts. A third aberrant splicing event results in the deletion of exon 4, while a fourth retains intron 3. These aberrantly spliced mRNA transcripts are not expected to result in functional Pax3 proteins. (J:3731)