A novel Rel protein and shortened isoform that differentially regulate antibacterial peptide genes in the silkworm Bombyx mori.
Two cDNAs encoding novel Rel proteins were cloned from the silkworm, Bombyx mori. These cDNA clones (BmRelA and BmRelB) showed identical nucleotide sequences except for the 5'-region. BmRelB cDNA derived probably from an alternatively spliced mRNA lacked 241 bp nucleotides at the 5'-region of the BmRelA cDNA, resulting in a loss of the first 52 amino acids. Expression of antibacterial peptide genes was strongly inhibited upon infection with Micrococcus luteus in transgenic silkworms in which BmRel gene expression was knocked down, suggesting that these two Rel proteins are involved in activation of antibacterial peptide genes. Co-transfection experiments indicated that BmRelB activated the Attacin gene strongly and other genes to a lesser extent, whereas BmRelA activated Lebocin 4 gene strongly and Attacin and Lebocin 3 genes very weakly. The Rel homology domain of BmRelA and BmRelB was shown to bind specifically to kappaB sites of antibacterial peptide genes. Proline-rich domains of the BmRels were necessary for activation of antibacterial peptide genes. These results illustrate that a minor structural change in Rel proteins can provoke a dramatic differential activation of antibacterial peptide genes, suggesting a novel regulatory mechanism for insect antibacterial peptide gene expression.
Tanaka
Hiromitsu
H
Innate Immunity Laboratory, National Institute of Agrobiological Sciences, Owashi 1-2, Tsukuba, Ibaraki 305-8634, Japan.
Yamamoto
Masafumi
M
Moriyama
Yuko
Y
Yamao
Masafumi
M
Furukawa
Seiichi
S
Sagisaka
Aki
A
Nakazawa
Hiroshi
H
Mori
Hajime
H
Yamakawa
Minoru
M
D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics* / Q000276:immunology; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D040461:Gene Components; D005786:Gene Expression Regulation / Q000276:immunology*; D005822:Genetic Vectors; D005982:Glutathione Transferase; D019476:Insect Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics* / Q000276:immunology; D016328:NF-kappa B / Q000378:metabolism; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics; D014162:Transfection
D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D018076:DNA, Complementary; D029721:Drosophila Proteins; D019476:Insect Proteins; D016328:NF-kappa B; D020033:Protein Isoforms; C101626:Rel protein, Drosophila; D014157:Transcription Factors; D005982:Glutathione Transferase