| Our study successfullly constructed the transgenic vector congtaing short fragmentdsRNAs of two essential genes (ie-1and lef-1) of BmNPV and two screening genes(gfpand neo).The stale transformed cells exhibited obvious resistance to BmNPV wheninoculated10-9diluted wild type BmNPV; in addition, the identified transgenicsilkworms also showed high efficacy of RNAi while infected BmNPV hydropolyvirusat a concentration of106/mL as a result of the mortality of transgenic silkwormsdecreased40%compared to the control groups.In this study, we also investigated the characteristics and functions of BmAchi, aBombyx mori homolog of DmAchi. Like DmAchi, BmAchi is predominantly expressedin the testes and ovaries. Four alternatively spliced isoforms could be isolated fromtestes, and two isoforms from ovaries. Quantitative polymerase chain reaction indicatedthat Bmachi was abundantly expressed in the testis of3rd instar larvae, when the testisis almost full of primary spermatocytes. The results of luciferase assays indicated thatBmAchi contains two adjacent acidic domains that activate the transcription of reportergenes. Immunofluorescence assay in BmN cells showed that the BmAchi protein waslocated mainly in the nucleus, and paraffin sections of testis showed that BmAchi wasgrossly expressed in primary spermatocytes and motile sperms. Consistent with the roleof DmAchi in Drosophila development, BmAchi significantly affected spermatiddifferentiation, as indicated by both hematoxylin-eosin staining of paraffin sections oftestis from Bmachi-small interfering RNA (siRNA)-injected male silkworms, and by theincidence of unfertilized eggs produced by crossing Bmachi-siRNA-injected males withnormal females. Co-immunoprecipitation experiments suggested that BmAchiinteracted with BmAly, and that they may recruit other factors to form a complex toregulate the genes required for meiotic divisions and spermatid differentiation. |
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