Two fibrinogen-related proteins (FREPs) in the razor clam (Sinonovacula constricta) with a broad recognition spectrum...

Area of Science:

• Marine biology
• Immunology
• Biochemistry

Background:

• Fibrinogen-related proteins (FREPs) containing only the fibrinogen-related domain are implicated in pathogen recognition.
• The immune mechanisms of bivalve mollusks, like razor clams, are crucial for understanding invertebrate immunity.

Purpose of the Study:

• To identify and characterize novel FREPs in the razor clam (Sinonovacula constricta).
• To investigate the role of these FREPs in the clam's immune response against microbial infections.

Main Methods:

• Identification and molecular characterization of two FREPs (ScFREP-1 and ScFREP-2) from Sinonovacula constricta.
• Analysis of mRNA expression patterns in different clam tissues and after microbial challenge.
• Biochemical assays to assess the binding and agglutination activity of recombinant ScFREPs against bacteria and pathogen-associated molecular patterns (PAMPs).

Main Results:

• Two novel FREPs, ScFREP-1 and ScFREP-2, were identified, each possessing a C-terminal fibrinogen-related domain.
• ScFREP-1 and ScFREP-2 mRNAs were ubiquitously expressed in adult clam tissues, with notable levels in gills and mantle.
• Expression of ScFREPs was significantly induced following microbe infection.
• Recombinant ScFREPs demonstrated binding and agglutination activity against both Gram-positive and Gram-negative bacteria, as well as specific PAMPs.

Conclusions:

• ScFREPs function as key pattern recognition receptors in razor clams.
• These proteins play a vital role in the innate immune system by recognizing conserved microbial molecules and mediating pathogen clearance through agglutination.