title: Delta tryptase is expressed in multiple human tissues, and a recombinant form has proteolytic activity.
abstract: Tryptases are neutral serine proteases selectively expressed in mast cells and have been implicated in the development of a number of inflammatory diseases including asthma. It has recently been established that the number of genes encoding human mast cell tryptases is much larger than originally believed, but it is not clear how many of these genes are expressed. A recent report suggested that the transcript for at least one of these genes, originally named mMCP-7-like tryptase, is not expressed. To further address this question, we screened tissue-specific RNA samples by RT-PCR, using primers designed to match the putative exonic sequence of this gene. We successfully generated and cloned the correctly sized RT-PCR product from mRNA isolated from the human mast cell-I cell line. Two distinct clones were identified whose nucleotide sequence matched the published sequence of the mMCP-7-like I and mMCP-7-like II genes. Transcripts were detected in a wide variety of human tissues including lung, heart, stomach, spleen, skin, and colon. A polyclonal antipeptide Ab that specifically recognizes the translated product of this transcript was used to demonstrate its expression in mast cells that reside in the colon, lung, and inflamed synovium. A recombinant form of this protein expressed in bacterial cells was able to cleave a synthetic trypsin-sensitive substrate, D-Ile-Phe-Lys pNA. These results suggest that the range of functional tryptases is larger than previously recognized. For simplicity, we suggest that the gene, transcripts, and corresponding protein product be named delta tryptase.
authors.affiliation: Inflammation Research Units, Department of Pathology, University of New South Wales, Sydney, Australia.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Wang
authors.forename: H Patrick
authors.initials: HP
authors.lastname: McNeil
authors.forename: Ahsan
authors.initials: A
authors.lastname: Husain
authors.forename: Ke
authors.initials: K
authors.lastname: Liu
authors.forename: Nicodemus
authors.initials: N
authors.lastname: Tedla
authors.forename: Paul S
authors.initials: PS
authors.lastname: Thomas
authors.forename: Mark
authors.initials: M
authors.lastname: Raftery
authors.forename: Garry C
authors.initials: GC
authors.lastname: King
authors.forename: Zhao Yan
authors.initials: ZY
authors.lastname: Cai
authors.forename: John E
authors.initials: JE
authors.lastname: Hunt
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003106:Colon / Q000201:enzymology; D018076:DNA, Complementary / Q000302:isolation & purification; D004789:Enzyme Activation / Q000235:genetics; D005753:Gastric Mucosa / Q000201:enzymology; D006801:Humans; D006868:Hydrolysis; D008168:Lung / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology; D009928:Organ Specificity / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012867:Skin / Q000201:enzymology; D013154:Spleen / Q000201:enzymology; D053802:Tryptases; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D053802:Tryptases