Molecular and Physiological Characterization of Two Novel Multirepeat β-Thymosins from Silkworm, Bombyx mori

Abstract

β-thymosin plays important roles in the development of the lymphatic system and the central nervous system in vertebrates. However, its role and function in invertebrates remain much less explored. Here, we firstly isolated a gene encoding β-thymosin in silkworm (Bombyx mori L.). Interestingly, this gene encodes two polypeptides, named as BmTHY1 and BmTHY2, via two different modes of RNA splicing. The recombinant proteins fused with an N-term GST tag were over-expressed in Escherichia coli (E. coli) and further purified to near homogenity to prepare mouse antibodies. The Western blot analysis showed that these proteins were expressed in various tissues and organs, as well as in different developmental stages. Amazingly, the expression of BmTHY2 was hugely increased during the pupae stage, indicating a specialized role in this period. The expression of these proteins was gradually decreased in BmN cells infected by BmNPV, suggesting they may play different roles in the virus infection. In addition, both BmTHY1 and BmTHY2 can interact with 14-3-3 of silkworm and Ubiquitin of BmNPV as shown by GST pull down and Co-IP assays, consistent with their roles in the regulation of the development of nervous system.

Thymosin FromBombyx moriIs Down-Regulated in Expression by BmNPV Exhibiting Antiviral Activity

“…Results from Western blotting and qRT-PCR showed that BmTHY protein expression and transcription were down-regulated when BmN cells were infected with BmNPV as time in culture increased, which is similar to the result of the recently reported study ( Ma et al 2015 ). However, these results are not consistent with those of previous studies on β-thymosin in Helicoverpa armigera (HaTHY), which demonstrated that HaTHY is up-regulated in response to H. armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) infection ( Zhang et al 2011 ).…”

Cloning, Expression and Effects of P. americana Thymosin on Wound Healing

“…For example, multimeric β-thymosin can promote actin polymerization, whereas β-thymosin is thought to be a sequester protein, which suggests that the function of these two kinds of thymosin behave differently [6]. In addition, owing to exon skip splicing, many varieties of thymosin in invertebrates have several isoforms, actually, they come from the same gene and the functions of different isoforms are different [15,16]. However, most researches about multimeric β-thymosin focused on its structural characterization, the style to connect with G-actin or the expression in mRNA level, and little information has been explored on its molecular function [16,17,18].…”

Identification and Characterization of BmVta1, a Bombyx mori (Lepidoptera: Bombycidae) Homologue for Vta1 That is Up-Regulated in Development

“…The protein expression was examined by 12% SDS–PAGE visualized by Coomassie Brilliant Blue R-250 staining. To further verify the expression of BmVta1, Western blot using an anti-His monoclonal antibody and Mass Spectrometry were performed as described previously ( Qin et al 2012 , Ma et al 2015 , You et al 2016 ).…”