Chp1^vac

An A to G transition was found in exon 6 at nucleotide 657, resulting in a glycine at codon 168 instead of an aspartic acid. This amino acid change occurs in the z position of the fourth EF hand of the protein in one of six residues involved in calcium binding. The base pair change also creates a novel splice donor site resulting in the expression of two abnormal transcripts. Both abnormal transcripts result in frameshifts that delete the second half of EF4. Quantitative real-time RT-PCR confirms the expression of all three transcripts in the cerebellum, with the correctly spliced missense transcript constituting about 30% of all transcripts. Western blot analysis detects 2 bands in cerebellar lysates from homozygous mutant mice but only 1 band in wild-type mice and an overall 70% reduction in protein levels in homozygous mutants compared to wild-type mice. (J:199873)