Homologous recombination replaced 19.2 kb of genomic sequence, containing all exons from exon 2 onwards, with a lacZ reporter cassette (including Kozak sequence and ATG start codon) and a loxP site flanked neomycin resistance gene cassette. Differential RNA-Seq analysis confirmed the loss of RNA expression in lungs from homozygous mice and the absence of an effect on the expression of neighboring genes.