Isolation and characterization of insect PC2-like prohormone convertase cDNA

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Prohormone or proprotein convertases (PCs) are essential serine proteases involved in the endoproteolytic processing of precursor proteins.
• This processing occurs at basic amino acid residues, crucial for the maturation of hormones, neuropeptides, and regulatory proteins.
• PCs belong to the subtilisin family of enzymes, playing vital roles across various biological systems.

Purpose of the Study:

• To identify and characterize novel prohormone convertase genes in the sheep blowfly, Lucilia cuprina.
• To investigate the evolutionary relationships of L. cuprina PCs with known invertebrate and vertebrate homologues.
• To analyze the expression pattern of the identified PC gene.

Main Methods:

• Screening of a Lucilia cuprina larval cDNA library.
• Isolation and sequencing of cDNAs encoding PC2-like enzymes.
• Bioinformatic analysis to determine amino acid identity and phylogenetic relationships.
• Northern blot analysis to detect gene expression.

Main Results:

• Two cDNAs encoding a PC2-like prohormone convertase were isolated from L. cuprina.
• The predicted 675 amino acid preproprotein, LcuPC2, showed highest identity to invertebrate and vertebrate PC2 homologues.
• LcuPC2 exhibited lower identity to known insect furin-like prohormone convertases.
• Northern blot analysis detected a signal at 2.5 kb, indicating gene expression.

Conclusions:

• A novel PC2-like prohormone convertase has been identified in Lucilia cuprina.
• LcuPC2 represents a distinct lineage of PC2 enzymes, with significant homology to vertebrate and other invertebrate PC2s.
• The findings contribute to understanding the diversity and evolution of prohormone processing enzymes in insects.