Endogenous regulatory and promoter sequences drive expression of Chc tagged at the N-terminal end with the synthetic Flag-4C peptide (MDYKDDDDKGSAGSFLNCCPGCCMEP - comprised of the Tag:FLAG peptide and the FlAsH (Tag:CALI(TC)) peptide separated by the peptide linker GSAGS). A 20 amino acid in-frame loxP site linker is found between Chc and the tag.