A neomycin resistance cassette flanked by loxP and lox71 was inserted into exon 1. A knock-in vector containing plox66-HL28NP was inserted along with a cre-expressing plasmid, resulting in the replacement of the neo with the knock-in vector. The vector contained lox66, IRES, human cDNA encoding the calcium channel, voltage-dependent, P/Q type, alpha 1A subunit gene from HL28NP (GenBank AB035726), a polyA signal and an FRT-flanked CAG-hygro gene. The human gene contained 28 polyglutamine repeats.