Mouse matriptase-2: identification, characterization and comparative mRNA expression analysis with mouse hepsin in adult and embryonic tissues.
We report the identification and characterization of mouse matriptase-2 (m-matriptase-2), an 811-amino-acid protein composed of an N-terminal cytoplasmic domain, a membrane-spanning domain, two CUB (complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domains, three LDLR (low-density-lipoprotein receptor class A) domains and a C-terminal serine-protease domain. All m-matriptase-2 protein domain boundaries corresponded with intron/exon junctions of the encoding gene, which spans approx. 29 kb and comprises 18 exons. Matriptase-2 is highly conserved in human, mouse and rat, with the rat matriptase-2 gene ( r-maltriptase-2 ) predicted to encode transmembrane and soluble isoforms. Western-blot analysis indicated that m-matriptase-2 migrates close to its theoretical molecular mass of 91 kDa, and immunofluorescence analysis was consistent with the proposed surface membrane localization of this protein. Reverse-transcription PCR and in-situ -hybridization analysis indicated that m-matriptase-2 expression overlaps with the distribution of mouse hepsin (m-hepsin, a cell-surface serine protease identified in hepatoma cells) in adult tissues and during embryonic development. In adult tissues both are expressed at highest levels in liver, kidney and uterus. During embryogenesis m-matriptase-2 expression peaked between days 12.5 and 15.5. m-hepsin expression was biphasic, with peaks at day 7.5 to 8.5 and again between days 12.5 and 15.5. In situ hybridization of embryonic tissues indicated abundant expression of both m-matriptase-2 and m-hepsin in the developing liver and at lower levels in developing pharyngo-tympanic tubes. While m-hepsin was detected in the residual embryonic yolk sac and with lower intensity in lung, heart, gastrointestinal tract, developing kidney tubules and epithelium of the oral cavity, m-matriptase-2 was absent in these tissues, but strongly expressed within the nasal cavity by olfactory epithelial cells. Mechanistic insight into the potential role of this new transmembrane serine protease is provided by its novel expression profile in embryonic and adult mouse.
Division of Vascular Biology, Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
John D
JD
Hooper
Luisa
L
Campagnolo
Goodarz
G
Goodarzi
Tony N
TN
Truong
Heidi
H
Stuhlmann
James P
JP
Quigley
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D004247:DNA; D004622:Embryo, Mammalian / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D008565:Membrane Proteins; D012333:RNA, Messenger; D004247:DNA; D012697:Serine Endopeptidases; C055645:hepsin; C485595:matriptase; C467801:matriptase 2