title: An immune-induced reeler protein is involved in the Bombyx mori melanization cascade.
abstract: In this study, we isolated two reeler cDNAs from bacteria-challenged larval fat bodies of the silkworm, Bombyx mori. A reeler domain spanned most of the coding regions of these two cDNAs, and their expression patterns were different in B. mori larval tissues. The reeler1 gene was strongly induced by Escherichia coli K12 and Bacillus subtilis in B. mori larval hemocytes, fat bodies and midguts, but reeler2 was expressed at extremely low levels in these tissues. We focused on the reeler1 gene for functional analysis. Interference by double-stranded reeler1 RNA in vivo led to reduced nodule formation in bacteria-injected larvae, while the injection of recombinant Reeler1 promoted nodule formation in reeler1 gene-silenced larvae, indicating that Reeler1 is involved in the nodulation response. Knockdown of the reeler1 gene significantly decreased phenoloxidase activity in bacteria-challenged larval hemolymph, while injection of recombinant Reeler1 enhanced phenoloxidase activity, suggesting that Reeler1 is involved in the prophenoloxidase activation cascade. Our results provide new mechanistic evidence about the melanization cascade in the insect immunity.
authors.affiliation: Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou, Zhejiang 310058, China.
authors.forename: Yan-Yuan
authors.initials: YY
authors.lastname: Bao
authors.forename: Jian
authors.initials: J
authors.lastname: Xue
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Zu-Yao
authors.initials: ZY
authors.lastname: Lv
authors.forename: Chuan-Xi
authors.initials: CX
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001412:Bacillus subtilis; D012831:Bombyx / Q000235:genetics / Q000254:growth & development / Q000276:immunology / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018076:DNA, Complementary; D004926:Escherichia coli; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005216:Fat Body / Q000276:immunology / Q000378:metabolism; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism; D006458:Hemolymph / Q000201:enzymology / Q000276:immunology; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007814:Larva / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000091042:Reelin Protein; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; D000091042:Reelin Protein; D014442:Monophenol Monooxygenase; D012697:Serine Endopeptidases