The exons 3-6 were replaced with PGK-neo cassette by targeted recombination. The resulting allele, when exon 2 is spliced onto exon 7, disrupt the open reading frame, introducing a premature stop codon at the beginning of exon 7. Western blot analysis using a C-terminal specific antibody onto whole cerebellar homogenates confirmed absence of full-length protein. However, a low level of a form of gene product with a reduced function resulting from exon1 spliced onto exon 7 that lacks most of the actin-binding domain encoded by exons 2-6 was expressed. This is a hypomorphic allele.