A family of peptidoglycan recognition proteins in the fruit fly Drosophila melanogaster

A family of peptidoglycan recognition proteins in the fruit fly Drosophila melanogaster

^*Umeå Centre for Molecular Pathogenesis, Umeå University, S-901 87 Umeå, Sweden; and ^†Department of Microbiology and ^§the Wenner–Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden

Edited by John H. Law, University of Arizona, Tucson, AZ, and approved September 26, 2000 (received for review August 24, 2000)

Abstract

Peptidoglycans from bacterial cell walls trigger immune responses in insects and mammals. A peptidoglycan recognition protein, PGRP, has been cloned from moths as well as vertebrates and has been shown to participate in peptidoglycan-mediated activation of prophenoloxidase in the silk moth. Here we report that Drosophila expresses 12 PGRP genes, distributed in 8 chromosomal loci on the 3 major chromosomes. By analyzing cDNA clones and genomic databases, we grouped them into two classes: PGRP-SA, SB1, SB2, SC1A, SC1B, SC2, and SD, with short transcripts and short 5′-untranslated regions; and PGRP-LA, LB, LC, LD, and LE, with long transcripts and long 5′-untranslated regions. The predicted structures indicate that the first group encodes extracellular proteins and the second group, intracellular and membrane-spanning proteins. Most PGRP genes are expressed in all postembryonic stages. Peptidoglycan injections strongly induce five of the genes. Transcripts from the different PGRP genes were found in immune competent organs such as fat body, gut, and hemocytes. We demonstrate that at least PGRP-SA and SC1B can bind peptidoglycan, and a function in immunity is likely for this family.

Footnotes

↵ ‡ Present address: Department of Cell and Molecular Biology, AstraZeneca R&D Lund, 221 87 Lund, Sweden.
↵ ¶ To whom reprint requests should be addressed. E-mail: dan.hultmark{at}ucmp.umu.se.
This paper was submitted directly (Track II) to the PNAS office.
Data deposition: The sequences reported in this paper have been deposited in the European Molecular Biology Laboratory/GenBank/DNA Data Base in Japan databases (accession nos. AF207535–AF207542).
Abbreviations:

PGRP,

peptidoglycan recognition protein;

EST,

expressed sequence tag