Identification and functional characterization of a peptidoglycan recognition protein from the cotton bollworm, Helicoverpa armigera.

Abstract

Peptidoglycan recognition proteins (PGRPs) specifically bind to peptidoglycans, and play crucial roles as pattern recognition receptors (PRRs) in mediating innate immune responses. In this study, we identified and characterized a PGRP (HaPGRP-D) from the cotton bollworm, Helicoverpa armigera. Sequence analysis indicated that HaPGRP-D is an amidase-type PGRP. Expression of HaPGRP-D was upregulated in the hemocytes of H. armigera larvae after injecting Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, or chromatography beads. To test the biological activity of HaPGRP-D, purified recombinant protein was prepared. Subsequent analysis showed that rHaPGRP-D (i) could bind and agglutinate Gram-negative E. coli and Gram-positive S. aureus in a zinc-dependent manner, (ii) functioned as an amidase to degrade peptidoglycans in the presence of Zn(2+) , (iii) strongly inhibited the growth of E. coli and S. aureus in the presence of Zn(2+) , (iv) could bind to the surface of hemocytes, (v) increased the phagocytosis of E. coli cells by hemocytes in vitro, and (vi) promoted hemocyte encapsulation on chromatography beads in vitro. These results suggest that HaPGRP-D plays important roles as PRR, amidase, and opsonin in H. armigera humoral and cellular immune responses.

• Authors: Li Li, Yu-Ping Li, Cai-Xia Song, Min Xiao, Jia-Lin Wang, Xu-Sheng Liu
• Journal: Archives of insect biochemistry and physiology (Arch Insect Biochem Physiol) Vol. 86 Issue 4 Pg. 240-58 (Aug 2014) ISSN: 1520-6327 [Electronic] United States
• PMID: 25044262 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 Wiley Periodicals, Inc.

Chemical References

• Carrier Proteins
• DNA Primers
• Peptidoglycan
• peptidoglycan recognition protein
• Zinc

Topics

• Animals
• Base Sequence
• Carrier Proteins (genetics, metabolism)
• DNA Primers (genetics)
• Escherichia coli (immunology)
• Gene Expression Profiling
• Gene Expression Regulation (immunology)
• Hemocytes (metabolism)
• Immunity, Innate (genetics)
• Molecular Sequence Data
• Moths (genetics, immunology, metabolism)
• Peptidoglycan (metabolism)
• Real-Time Polymerase Chain Reaction
• Reverse Transcriptase Polymerase Chain Reaction
• Sequence Analysis, DNA
• Staphylococcus aureus (immunology)
• Zinc