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International Journal of Genomics
Volume 2013 (2013), Article ID 269609, 8 pages
Research Article

The Expression, Purification, and Characterization of a Ras Oncogene (Bras2) in Silkworm (Bombyx mori)

1College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China
2Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, China
3School of Pharmacy, Xuzhou Medical College, Xuzhou 221004, China
4Department of Obstetrics and Gynecology, Yong Loo Lin School of Medicine, National University Health System, Singapore 119228
5Agilent Technologies Singapore, Singapore 117681

Received 4 January 2013; Revised 10 April 2013; Accepted 28 April 2013

Academic Editor: Graziano Pesole

Copyright © 2013 Zhengbing Lv et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The Ras oncogene of silkworm pupae (Bras2) may belong to the Ras superfamily. It shares 77% of its amino acid identity with teratocarcinoma oncogene 21 (TC21) related ras viral oncogene homolog-2 (R-Ras2) and possesses an identical core effector region. The mRNA of Bombyx mori Bras2 has 1412 bp. The open reading frame contains 603 bp, which encodes 200 amino acid residues. This recombinant BmBras2 protein was subsequently used as an antigen to raise a rabbit polyclonal antibody. Western blotting and real-time PCR analyses showed that BmBras2 was expressed during four developmental stages. The BmBras2 expression level was the highest in the pupae and was low in other life cycle stages. BmBras2 was expressed in all eight tested tissues, and it was highly expressed in the head, intestine, and epidermis. Subcellular localization studies indicated that BmBras2 was predominantly localized in the nuclei of Bm5 cells, although cytoplasmic staining was also observed to a lesser extent. A cell proliferation assay showed that rBmBras2 could stimulate the proliferation of hepatoma cells. The higher BmBras2 expression levels in the pupal stage, tissue expression patterns, and a cell proliferation assay indicated that BmBras2 promotes cell division and proliferation, most likely by influencing cell signal transduction.