Bombyx mori Metal Carboxypeptidases12 (BmMCP12) Is Involved in Host Protection Against Viral Infection

Area of Science:

• Insect pathology
• Molecular biology
• Biochemistry

Background:

• Baculoviruses, particularly Bombyx mori nucleopolyhedrovirus (BmNPV), cause significant economic losses in the sericulture industry.
• The anti-viral defense mechanisms of silkworms against BmNPV remain largely uncharacterized.
• Carboxypeptidases are implicated in insect immunity, but their specific roles in silkworm defense against pathogens are poorly understood.

Purpose of the Study:

• To identify and characterize silkworm carboxypeptidases involved in the defense against BmNPV infection.
• To investigate the function of Bombyx mori metal carboxypeptidases12 (BmMCP12) in the silkworm's immune response to BmNPV.

Main Methods:

• Gene identification and sequence analysis of Bombyx mori metal carboxypeptidases12 (BmMCP12).
• Analysis of BmMCP12 expression patterns in silkworm tissues and cells using qRT-PCR and Western blot.
• Functional studies involving gene overexpression and knockout in silkworms and cell lines to assess BmNPV replication and resistance.

Main Results:

• The homologous gene Bombyx mori metal carboxypeptidases12 (BmMCP12), related to mammalian CPA2, was identified and found to possess a Zn-pept domain.
• BmMCP12 is primarily located in the cytoplasm and highly expressed in the silkworm midgut; its expression increases in BmN-SWU1 cells post-BmNPV infection.
• Overexpression of BmMCP12 inhibited BmNPV replication, while gene knockout led to increased susceptibility to BmNPV, evidenced by reduced resistance in transgenic silkworms.

Conclusions:

• BmMCP12 plays a crucial role in the silkworm's innate immunity against BmNPV.
• This study elucidates the function of a silkworm carboxypeptidase in antiviral defense, providing novel insights into silkworm-pathogen interactions.
• BmMCP12 represents a potential new target for developing strategies to prevent and control BmNPV disease in silkworms.