Grm1^crv4

This mutation arose at the Institut Pasteur. Genetic mapping localized it to the vicinity of Grm1, of which it was shown to be an allele by its failure to complement a targeted mutation of the gene. A larger than wild-type transcript was amplified by RT-PCR from mutant cerebella; sequence analysis of the cDNA revealed a 139-base pair insertion between exons 4 and 5. A 190-base pair LTR fragment interrupting intron 4 was found to alter splicing of the transcript to create a new exon comprising 23 bp from the intron and 116 bp from the LTR fragment, including an in-frame termination codon. No wild-type transcript was amplified by PCR and no immunoreactive protein was detected by western blot or immunohistochemical analysis of homozygous mutant cerebella. (J:112290)