GTSF1L is a 148 amino acid protein that exists as two alternatively spliced isoforms. Belonging to the evolutionarily conserved UPF0224 (FAM112) family, GTSF1L contains one CHHC-type zinc finger, which may have contributed to the architectural and functional diversity observed in the CHHC zinc finger containing proteins. GTSF1L’s CHHC zinc finger does not show sequence similarity to any known or previously characterized zinc finger domain. Necessary for metal ion binding, GTSF1L is up-regulated in CD133+ cells. GTSF1L is located on chromosome 20, which consists of approximately 63 million bases and 600 genes. Chromosome 20 contains a region with numerous genes expressed in the epididymis which are thought to be important for seminal production and may be potential targets for male contraception.