title: Downregulation of the Musca domestica peptidoglycan recognition protein SC (PGRP-SC) leads to overexpression of antimicrobial peptides and tardy pupation.
abstract: PGRP (peptidoglycan recognition protein) is a conserved protein family that recognizes the peptidoglycan in bacterial cell wall and causes the activation of various innate immune responses. Previous studies have reported that PGRP-SCs in Drosophila dampen the activation of Immune Deficiency (Imd) pathway to microbial infection, and participate in the lifespan extension of the insects. To facilitate understanding the function of PGRP-SCs from an evolutionary angle, we identified and functionally characterized the PGRP-SC gene in the housefly Musca domestica, a species that has adapted to a septic environment much harsher than the natural habitat of Drosophila. The gene designated as MdPGRP-SC was found most abundantly expressed in the 3rd instar larvae, and is expressed at this developmental stage predominantly in the gut. MdPGRP-SC was virtually unchanged in whole larvae after a septic injury at the second larval instar, while two antimicrobial peptides (AMPs), diptericin and attacin, were upregulated in the first 24h but not later. Through dsRNA microinjection, MdPGRP-SC was knocked down by RNA interference (RNAi), and caused the significant increased expression of diptericin and attacin. The pupation of MdPGRP-SC-depleted larvae was severely suppressed compared to controls. Opposite to the expression trend of MdPGRP-SC, a spontaneous active expression of diptericin and attacin was found in pre-pupae but not in third instar larvae. Taken together, our study reveals that downregulation of MdPGRP-SC leads to the overexpression of the AMPs, and is involved in the larvae-to-pupa transition of housefly.
authors: College of Life Sciences, Hebei University, Baoding, Hebei, China.
authors: Yifu
authors: Y
authors: Gao
authors: College of Life Sciences, Hebei University, Baoding, Hebei, China.
authors: Ting
authors: T
authors: Tang
authors: College of Life Sciences, Hebei University, Baoding, Hebei, China.
authors: Jihai
authors: J
authors: Gu
authors: College of Life Sciences, Hebei University, Baoding, Hebei, China.
authors: Lingling
authors: L
authors: Sun
authors: Department of Pathology, Yale University, New Haven, CT, USA.
authors: Xiaobin
authors: X
authors: Gao
authors: Department of Pathology, Yale University, New Haven, CT, USA.
authors: Xianyong
authors: X
authors: Ma
authors: Department of Pathology, Yale University, New Haven, CT, USA; Affiliated Hospital of Hebei University, Baoding, Hebei, China.
authors: Xiaochun
authors: X
authors: Wang
authors: College of Life Sciences, Hebei University, Baoding, Hebei, China. Electronic address: liufengsong@hbu.edu.cn.
authors: Fengsong
authors: F
authors: Liu
authors: Department of Pathology, Yale University, New Haven, CT, USA. Electronic address: jianhui.wang@yale.edu.
authors: Jianhui
authors: J
authors: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000276:immunology; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006793:Houseflies / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D007814:Larva; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D011679:Pupa / Q000235:genetics / Q000254:growth & development; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D023181:Antimicrobial Cationic Peptides; D002352:Carrier Proteins; D018076:DNA, Complementary; D012333:RNA, Messenger; C118897:peptidoglycan recognition protein
keywords: Antimicrobial peptides; Innate immunity; Musca domestica; PGRP-SC; Pupation