Alternative Splicing Of Antitrypsin In The Silkworm, Bombyx Mori

The control of eukaryotic gene expression is currently a key focal point of life science research. Reseach has shown that mRNA affects gene regulation and expression,so splicing,espacially alternative splicing of RNA,will affect the control of eukaryotic gene expression. Alternative splicing is a mechanism that increases transcriptome and proteome diversifications by generating multiple mRNA products from a single gene.The pre-RNAs altematvie splicing greatly increases the diversiyty of proteins and the complexity of genes experssion.It can control the quantitation expression of proteins highly performance. Alternative splicing influences the growth of organism and play an important significance in cell differentiation, development; physiologic function and pathologic state.The silkworm was an important economic insect, furthermore, it was one of the model creatures in molecular biology.Silkworm was a typical representative in Lepidoptera. The non-specific humoral immunity actor is a type of humoral factor in hemolymph and mucus.In 1990, Hiroshi Takagi has confirmed that silkworm antitrypsin (SW-AT) is a humoral factor.It is one class of serine proteinas inhibitors, which play a major role in regulating the proteinase activity in the insect haemolymph. SW-AT can suppress the appearance of phenoloxidase activity, and may function in the prophenoloxidase activating cascade in the hemolymph, which is thought to be an important defense system in insects.So,the study researched the alternative splicing of SW-AT initially. First, using the software of bioinformatics, get 100 EST of SW-AT and induced them to four isoforms.They is consisented of 10 exons and 9 introns,the ninth exon is different. To bestride intron , the study designed the specificity primer. Using RT-PCR and realtime quantitative PCR methods , the study confirmed the four isoforms and investigated the expression level in various larval and pupal organs, and the expression quantity of the fat body in different developmental ages. The results indicate four isoforms were expressed in most of the organs and had a high expression level in fat body.The copy number of the first isoform is up to 6 000 per 1 000 Bm-Actin A3 gene,but the expression level of the fourth isoform is lowest,110 copies. Suppose the fourth isoform may be a new form. High and low temperature treatment indicate SW-AT is very sensitive,the expression quantity is more three times higher than conventional feeding,this may be correlated to the stress function. The fundamental mechanism and function of alternative splicing of SW-AT should be studied advancely.