Alternative titles; symbolsTRYPTASE, DELTAMAST CELL PROTEASE 7-LIKEMCP7-LIKEHGNC Approved Gene Symbol: TPSD1Cytogenetic location: 16p13.3 Genomic coordinates...
Alternative titles; symbols
HGNC Approved Gene Symbol: TPSD1
Cytogenetic location: 16p13.3 Genomic coordinates (GRCh38): 16:1,256,068-1,259,007 (from NCBI)
Tryptases are serine proteases implicated in asthma and are highly expressed in human mast cells. They are derived from at least 4 nonallelic genes clustered on chromosome 16p13.3: TPSAB1 (191080), which represents the alpha and beta-I tryptase alleles; TPSB2 (191081), which represents the beta-II and beta-III tryptase alleles; TPSG1 (609341); and TPSD1 (Pallaoro et al., 1999; Caughey et al., 2000).
▼ Cloning and Expression
By BAC analysis, Pallaoro et al. (1999) identified the TPSD1 gene, which they called MCP7 (TPSAB1; 191080)-like, within a tryptase gene cluster on chromosome 16. They identified 2 alleles of the TPSD1 gene, which they called MCP7-like I and MCP7-like II.
By RT-PCR of a mast cell line cDNA library, Wang et al. (2002) obtained cDNAs for MCP7-like I and MCP7-like II, which they called delta-I and delta-II tryptase. The delta-I and delta-II variants differ at only 2 nucleotides, and the proteins differ at only 1 amino acid. Compared with the alpha and beta tryptases, the deduced delta tryptase has a premature translation termination codon, resulting in a proenzyme of 235 amino acids and a mature protein of 205 amino acids. Delta tryptase, however, retains the critical catalytic triad, although it shows complete loss of 1 of the 7 loops that form the tryptase substrate-binding cleft. RT-PCR detected delta tryptase expression in several adult and fetal tissues. Expression was most abundant in colon and lung, lower in heart and stomach, and just detectable in spleen. Western blot analysis detected delta tryptase at an apparent molecular mass of less than 30 kD. Immunohistochemical analysis detected delta tryptase within mast cells in a range of tissues. Staining in colon tissue showed that most positive cells were in the mucosa, specifically in the lamina propria between the crypts.
▼ Gene Function
Wang et al. (2002) found that recombinant delta tryptase expressed in bacterial cells showed tryptase activity against several synthetic substrates.
▼ Gene Structure
Pallaoro et al. (1999) determined that the TPSD1 gene contains 6 exons.
By BAC analysis and FISH, Pallaoro et al. (1999) mapped the TPSD1 gene to a tryptase cluster on chromosome 16p13.3.