A pattern recognition protein for peptidoglycan. Cloning the cDNA and the gene of the silkworm, Bombyx mori.
Peptidoglycan recognition protein (PGRP) specifically binds to peptidoglycan and is considered to be one of the pattern recognition proteins in the innate immunity of insect. The PGRP is an essential component for peptidoglycan to trigger the prophenoloxidase cascade that is now recognized to be an important insect defense mechanism. We cloned cDNA encoding PGRP from the silkworm fat body cDNA library. Northern blot analysis showed that the PGRP gene is constitutively expressed in the fat body, epithelial cell, and hemocytes of naive silkworms. Furthermore, a bacterial challenge intensified the gene expression, with the maximal period being from 6 to 36 h after infection. The upstream sequence of the cloned PGRP gene was shown to contain putative cis-regulatory elements similar to the NF-kappaB-like element, interferon-response half-element, and GATA motif element, which have been found in the promoters of the acute phase protein genes of mammals and insects. A homology search revealed that the homologs of silkworm PGRP are present in mice, nematodes, and bacteriophages. This suggests that the recognition of peptidoglycan as foreign is effected in both vertebrates and invertebrates by PGRP homologs with an evolutionally common origin.
Ochiai
M
M
Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan. ochiai@orange.lowtem.hokudai.ac.jp
Ashida
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005091:Exons; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D018076:DNA, Complementary; D010457:Peptidoglycan; D012333:RNA, Messenger; C118897:peptidoglycan recognition protein