title: Identification, gene expression and immune function of the novel Bm-STAT gene in virus-infected Bombyx mori.
abstract: Genes in the signal transducer and activator of transcription (STAT) family are vital for activities including gene expression and immune response. To investigate the functions of the silkworm Bombyx mori STAT (Bm-STAT) gene in antiviral immunity, two Bm-STAT gene isoforms, Bm-STAT-L for long form and Bm-STAT-S for short form, were cloned. Sequencing showed that the open reading frames were 2313 bp encoding 770 amino acid residues for Bm-STAT-L and 2202 bp encoding 734 amino acid residues for Bm-STAT-S. The C-terminal 42 amino acid residues of Bm-STAT-L were different from the last 7 amino acid residues of Bm-STAT-S. Immunofluorescence showed that Bm-STAT was primarily distributed in the nucleus. Transcription levels of Bm-STAT in different tissues were determined by quantitative PCR, and the results revealed Bm-STAT was mainly expressed in testes. Western blots showed two bands with molecular weights of 70 kDa and 130 kDa in testes, but no bands were detected in ovaries by using anti-Bm-STAT antibody as the primary antibody. Expression of Bm-STAT in hemolymph at 48 h post infection with B. mori macula-like virus (BmMLV) was slightly enhanced compared with controls, suggesting a weak response induced by infection with BmMLV. Hemocyte immunofluorescence showed that Bm-STAT expression was elevated in B. mori nucleopolyhedrovirus (BmNPV)-infected cells. Moreover, resistance of BmN cells to BmNPV was reduced by downregulation of Bm-STAT expression and increased by upregulation. Resistance of BmN cells to BmCPV was not significantly improved by upregulating Bm-STAT expression. Therefore, we concluded that Bm-STAT is a newly identified insect gene of the STAT family. The JAK-STAT pathway has a more specialized role in antiviral defense in silkworms, but JAK-STAT pathway is not triggered in response to all viruses.
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China.
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China.
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Kumar
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China.
authors.forename: Huanyan
authors.initials: H
authors.lastname: Ma
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Hu
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China.
authors.forename: Guangli
authors.initials: G
authors.lastname: Cao
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China.
authors.forename: Renyu
authors.initials: R
authors.lastname: Xue
authors.affiliation: School of Biology & Basic Medical Science, Soochow University, Suzhou 215123,China; National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China. Electronic address: gongcl@suda.edu.cn.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Gong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics* / Q000276:immunology / Q000821:virology; D015536:Down-Regulation; D005260:Female; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006458:Hemolymph; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D053612:Janus Kinases / Q000235:genetics / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D050791:STAT Transcription Factors / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA / Q000662:veterinary; D015398:Signal Transduction; D015854:Up-Regulation; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D020033:Protein Isoforms; D050791:STAT Transcription Factors; D053612:Janus Kinases; D001616:beta-Galactosidase
keywords: Antiviral defense; Bm-STAT gene; Bombyx mori; Expression pattern