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MHV-3 induced prothrombinase is encoded by musfiblp
1Department of Pathology and Laboratory Medicine, University of Texas Health Sciences Center, Houston, USA.
Abstract:
Previously, we demonstrated induction of a unique macrophage prothrombinase, PCA, in MHV-3 infected BALB/cJ mice. By immunologic screening, a clone representing PCA was isolated from a cDNA library and sequenced. The sequence identified this clone as representing part of a gene, musfiblp, that encodes a fibrinogen-like protein. Six additional clones were isolated, and one clone, p11-3-1, encompassed the entire coding region of musfiblp. Murine macrophages did not constitutively express musfiblp, but when infected with MHV-3, synthesized musfiblp-specific mRNA. Musfiblp mRNA induction was earlier and significantly greater in BALB/cJ than A/J macrophages. Prothrombinase activity was demonstrate when musfiblp was expressed from p11-3-1 in RAW 264.7 cells. These data suggest that musfiblp encodes the MHV-induced prothrombinase.
Insights
Researchers identified a fibrinogen-like protein, musfiblp, as the macrophage prothrombinase (PCA) induced by MHV-3 infection in mice. This protein
Area of Science:
- Immunology
- Molecular Biology
- Virology
Background:
- A unique macrophage prothrombinase, PCA, was previously shown to be induced by MHV-3 infection in BALB/cJ mice.
- The identity and genetic basis of this prothrombinase were yet to be fully elucidated.
Purpose of the Study:
- To identify the gene encoding the MHV-3-induced macrophage prothrombinase (PCA).
- To characterize the expression of the identified gene in murine macrophages during MHV-3 infection.
Main Methods:
- Immunologic screening of a cDNA library from MHV-3 infected BALB/cJ mice.
- Sequencing of isolated cDNA clones to identify the gene.
- Analysis of musfiblp mRNA expression in murine macrophages (BALB/cJ and A/J) after MHV-3 infection.
- Expression of musfiblp in RAW 264.7 cells to assess prothrombinase activity.
Main Results:
- A cDNA clone representing PCA was identified as part of the musfiblp gene, which encodes a fibrinogen-like protein.
- Murine macrophages did not constitutively express musfiblp but synthesized musfiblp-specific mRNA upon MHV-3 infection.
- MHV-3 induced significantly earlier and greater musfiblp mRNA expression in BALB/cJ macrophages compared to A/J macrophages.
- Expression of musfiblp from a full-length clone (p11-3-1) in RAW 264.7 cells demonstrated prothrombinase activity.
Conclusions:
- The data strongly suggest that musfiblp encodes the prothrombinase induced by MHV-3 infection in macrophages.
- Musfiblp expression is differentially regulated by MHV-3 infection in a mouse strain-dependent manner.
- This finding provides a molecular basis for understanding the host-pathogen interaction involving MHV-3 and macrophage prothrombinase activity.