Effect of BBX-B8 overexpression on development, body weight, silk protein synthesis and egg diapause of Bombyx mori
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Bombyxin (BBX) is an insulin-like peptide exists in the silkworm Bombyx mori. Our previous studies on the effects of inhibiting BBX-B8 expression found that BBX-B8 is important for the development of organ, reproduction and trehalose metabolism in the silkworms. In this paper, we investigated the expression profile of the BBX-B8 gene and effect of BBX-B8 overexpression on the development, body weight, silk protein synthesis and egg diapause of B. mori to further understand BBX-B8 functions. BBX-B8 gene expression could be detected in the brains, midguts, anterior silkglands, ovaries, testes, fat bodies, hemolymph, malpighian tubules and embryos by RT-PCR, however it was mainly expressed in the brain. Western blots showed that the change in BBX-B8 expression was not obvious in the brain of 1- to 4-day-old larvae of fifth instar silkworms, but expression increased substantially at 5- to 6-day-old larvae of fifth instar silkworms. Transgenic silkworms overexpressing BBX-B8 were obtained by introducing non-transposon transgenic vector pIZT-B8 containing a BBX-B8 gene driven by Orgyia pseudotsugata nucleopolyhedrovirus IE2 promoter into the genome. Development duration of the transgenic silkworms was delayed by 2.5–3.5 days. Cocoon shell weight of transgenic silkworms was reduced by 4.79 % in females and 7.44 % in males, pupal weight of transgenic silkworms was reduced 6.75 % in females and 13.83 % in males compared to non-transgenic silkworms, and 5.56–14.29 % of transgenic moths laid nondiapausing eggs. All results indicated that BBX-B8 plays an important role in the development, silk protein synthesis and egg diapause of silkworm.
KeywordsBombyxin BBX-8 gene Development Silk protein synthesis Egg diapause
We gratefully acknowledge the financial support of the National Basic Research Program of China (973 Program, 2012CB114600), the National Natural Science Foundation of China (31272500), State Key Laboratory of Silkworm Genome Biology (SKLSGB201200011) and a project funded by the Priority Academic Program of Development of Jiangsu Higher Education Institutions. We also thank Professor Iwami Masafumi (Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University) for kindly providing mouse anti-Bombyxin II monoclonal antibody.
- Broughton SJ, Piper MD, Ikeya T, Bass TM, Jacobson J, Driege Y, Martinez P, Hafen E, Withers DJ, Leevers SJ, Partridge L (2005) Longer lifespan, altered metabolism, and stress resistance in Drosophila from ablation of cells making insulin-like ligands. Physiology 102:3105–3110Google Scholar
- Brown MR, Clark KD, Gulia M, Zhao Z, Garczynski SF, Crim JW, Suderman RJ, Strand MR (2008) An insulin-like peptide regulates egg maturation and metabolism in the mosquito Aedes aegypti. Biochemistry 105:5716–5721Google Scholar
- Iwami M, Sakurai S, Nagasawa H (1998) Non-vertebrate’s hormone [M]. Japanese Comparison Internal secretion Academic society Compilation. Acad Soc Publ Cent 12:37–70Google Scholar
- Kondo H, Ino M, Suzuki A, Ishizaki H, Iwami M (1996) Multiple gene copies for bombyxin, an insulin-related peptide of the silkmoth Bombyx mori: structural signs for gene rearrangement and duplication responsible for generation of multiple molecular forms of bombyxin. J Mol Biol 259:926–937CrossRefPubMedGoogle Scholar
- Mizoguchi A, Ishizaki H, Nagasawa H, Kataoka H, Isogai A, Tamura S, Suzuki A, Fujino M, Kitada C (1987) A monoclonal antibody against a synthetic fragment of bombyxin (4 K-prothoracicotropic hormone) from the silkmoth, Bombyx mori: characterization and immunohistochemistry. Mol Cell Endocrinol 51:227–235CrossRefPubMedGoogle Scholar
- Sebastian G, Linda P (2010) The functions of insulin-like peptides in insects. In: Clemmons DR, Robinson ICAF, Christen Y (eds) IGFs: local repair and survival factors throughout life span. Springer, Berlin Heidelberg, pp 105–124Google Scholar
- Zheng X, Lu Y, Cao G, Xue R, Shen W, Gong C (2010) Effects of the expression of repressive insulin-like peptide gene BBX-B8 on stress resistance of the silkworm, Bombyx mori. Sci Seric 36:0590–0596Google Scholar