Alternative titles; symbols
HGNC Approved Gene Symbol: SPINT3
Cytogenetic location: 20q13.12 Genomic coordinates (GRCh38) : 20:45,512,461-45,515,622 (from NCBI)
Kunitz domains contain 50 to 60 amino acids, including 6 cysteines that form 3 disulfide bonds, and are typically found in protease inhibitors. SPINT3 is a Kunitz domain-containing protein expressed specifically in epididymis (Clauss et al., 2011).
The WFDC locus on human chromosome 20 encompasses several genes encoding WFDC-type protease inhibitors (e.g., WFDC2; 617548), some of which also contain Kunitz domains (e.g., EPPIN; 609031). By searching the WFDC locus for genes encoding protease inhibitors with Kunitz domains only, followed by 5-prime and 3-prime RACE of an epididymis cDNA library, Clauss et al. (2011) cloned SPINT3. The 89-amino acid SPINT3 protein has a 24-amino acid N-terminal signal peptide followed by a Kunitz domain. The processed, secreted protein has a calculated molecular mass of 7.6 kD. PCR analysis of human tissues showed that SPINT3 is predominantly expressed in epididymis.
Clauss et al. (2011) determined that the SPINT3 gene contains 2 exons and spans about 3.2 kb. The upstream region lacks a conventional TATA box, but it has an AT-rich sequence, TAAAAT, 26-bp upstream of the transcription initiation site.
By analysis of a BAC/YAC contig, genomic sequence analysis, and database analysis, Fossey et al. (2001) mapped the SPINT3 gene to chromosome 20q12-q13.1.
By sequence analysis, Clauss et al. (2011) mapped the SPINT3 gene to chromosome 20q13.1.
Clauss, A., Persson, M., Lilja, H., Lundwall, A. Three genes expressing Kunitz domains in the epididymis are related to genes of WFDC-type protease inhibitors and semen coagulum proteins in spite of lacking similarity between their protein products. BMC Biochem. 12: 55, 2011. [PubMed: 21988899] [Full Text: https://doi.org/10.1186/1471-2091-12-55]
Fossey, S. C., Mychaleckyj, J. C., Pendleton, J. K., Snyder, J. R., Bensen, J. T., Hirakawa, S., Rich, S. S., Freedman, B. I., Bowden, D. W. A high-resolution 6.0-megabase transcript map of the type 2 diabetes susceptibility region on human chromosome 20. Genomics 76: 45-57, 2001. [PubMed: 11549316] [Full Text: https://doi.org/10.1006/geno.2001.6584]