title: Novel protein of IBP from silkworm, Bombyx mori, involved in cytoplasmic polyhedrosis virus infection.
abstract: In the present study, the full-length cDNA of a novel insulin-related peptide-binding protein (named BmIBP2) was identified from silkworm, Bombyx mori, using rapid amplification of cDNA ends. The full-length cDNA of BmIBP2 is 1293 bp, consisting of a 5'-terminal untranslated region (UTR) of 61 bp, and a 3'-UTR of 335 bp with a poly-adenylation signal sequence AATAAA and a poly (A) tail. The BmIBP2 cDNA encodes a polypeptide of 298 amino acids, including an IG domain and an IGc2 domain, with a theoretical isoelectric point of 5.73 and a predicted molecular weight of 33.1 kDa. The BmIBP2 also has a signal peptide of 23 amino acids and a potential N-glycosylation site. The sequence similarity and phylogenic analysis indicated that BmIBP2 belongs to the group of invertebrates IBP and is closer to IGFBP7 than to the other IGFBPs in vertebrates. These findings suggest that BmIBP2 is a putative homolog of vertebrate endocrine factor IGFBP7 and has a functional similarity. By fluorescent quantitative real-time polymerase chain reaction, mRNA transcripts of BmIBP2 were mainly detected in the midgut but were hardly detectable in the hemocytes, vasa mucosa, fat body, silk gland, head, testicle, ovary, and spiracle. After the silkworm larvae were infected by B. mori cytoplasmic polyhedrosis virus (BmCPV), a significant up-regulation in the relative expression level of BmIBP2 was found. All the results suggested that BmIBP2 is a novel protein that plays an important role in the insulin-signal pathway and in the immune response of silkworm to BmCPV infection.
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
authors.forename: Xiang-yuan
authors.initials: XY
authors.lastname: Deng
authors.forename: He-Ying
authors.initials: HY
authors.lastname: Qian
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Guang-xing
authors.initials: GX
authors.lastname: Qin
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.forename: Zhong-yuan
authors.initials: ZY
authors.lastname: Shen
authors.forename: Xi-jie
authors.initials: XJ
authors.lastname: Guo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics* / Q000276:immunology / Q000821:virology*; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D019476:Insect Proteins / Q000235:genetics* / Q000276:immunology; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D012087:Reoviridae / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D018969:Insulin-Like Growth Factor Binding Proteins