Recombineering methods in bacterial cells were used to insert the codon-improved cre open reading frame and FRT-flanked ampicillin resistance gene after the ATG site of the Slc17a6 locus contained in BAC clone RP23-84M15. Insertion of the targeting construct resulting in inactivation of the Slc17a6 gene in the BAC. Flpe recombinase was induced in the bacterial cells and the ampicillin cassette was excised. The purified 201 kb final construct was injected into the pronuclei of C57BL/6 zygotes. Three positive founders were produced. All founders exhibited similar restricted cre expression in the spinal cord, so a line produced from one founder was analyzed further.