cDNA cloning, characterization and gene expression of nitric oxide synthase from the silkworm, Bombyx mori.
Molecular cloning and nucleotide sequencing of cDNA encoding Bombyx mori nitric oxide synthase (BmNOS) was conducted to analyse its possible role in insect immunity. The amino acid sequence deduced from the BmNOS cDNA showed 84%, 54% and 53% identity with those of NOSs from Manduca sexta, Drosophila melanogaster and Rhodonius prolixus. Recombinant BmNOS produced in insect cells using baculovirus was found to require NADPH, Ca2+, calmodulin and tetrahydrobiopterin (BH4) for its activity. The BmNOS gene was constitutively expressed at a low level in the larval fat body, haemocyte, Malpighian tubule and midgut, and adult antenna, and induced strongly in the fat body by lipopolysaccharide (LPS), suggesting that the BmNOS gene plays different physiological roles in different tissues. Injection of NO donors that produce NO in vivo induced the gene expression of an antibacterial peptide, cecropin B, strongly suggesting that NO produced by BmNOS following LPS stimulation is involved in signal transduction as a signalling molecule for immune gene expression.
Imamura
M
M
Innate Immunity Laboratory, National Institute of Agrobiological Sciences, Tsukuba, Japan.
Yang
J
J
Yamakawa
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary; D015870:Gene Expression; D019476:Insect Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D019476:Insect Proteins; D020030:Nitric Oxide Donors; D011993:Recombinant Fusion Proteins; C031162:cecropin B protein, Insecta; D019001:Nitric Oxide Synthase