Genomic structure and chromosomal localization of the human cathepsin O gene (CTSO)

The human gene encoding cathepsin O, a cysteine proteinase from the papain superfamily, has been cloned and its overall organization established. The gene (HGMW-approved symbol CTSO) is composed of eight coding exons and seven introns and spans more than 30 kb. The number and distribution of exons and introns differ from those reported for other human cysteine proteinases, indicating that these genes are not closely related. Chromosomal localization of CTSO revealed that it maps to chromosome 4q31-q32, which is a unique location for all cysteine proteinases mapped to date.