DNA sequence comprising the beta-galactosidase (lacZ) reporter gene and a loxP site flanked neomycin resistance gene driven by human UBC and bacterial EM7 promoters, replaced a 32 kbp region of the target gene spanning exons 4 to 21. Severely reduced transcription from this knock-out allele was shown by qRT-PCR. No lacZ activity was detected by either qRT-PCR or enzymatic assays. (J:243171)