Expression Profiles of a Reporter Gene Driven by Differently Truncated Promoters of Fibroin Heavy Chain Gene in Bombyx mori Tissues

In order to explore the regulation mechanism of fibroin heavy chain gene in silkworm (Bombyx mori),the recombinant AcMNPV was used as the transfer vector and green fluorescent protein (EGFP) gene was used as the reporter gene to investigate the expression profiles of the reporter gene in silkworm tissues of the 5th instar larvae driven by differently truncated promoters of fibroin heavy chain gene (FibH) (-2 127 /+23,-925 /+23 and-238 /+23). The results showed that there was ectopic expression of EGFP in fat body and hemocyte which was driven by three FibH promoters of various lengths. Green fluorescence could be observed directly on silkworm cuticle under fluorescence microscope. The three promoters of various lengths could initiate transcription of EGFP efficiently in posterior silk gland and produced green fluorescent light. Promoters of 0.9KH and 0.2KH could initiate transcription of EGFP in middle silk gland and yielded green fluorescent light. That of 2.1KH could initiate transcription of EGFP but no green fluerescent light was detected. All three promoters could also drive ectopic expression of EGFP in Sf9 cultured cells. The above results revealed that the promoter of fibroin heavy chain gene does not have strict tissue specificity.