JAK-STAT signaling pathway shared by a variety of cytokines was discovered in recent years. It plays an important role in growth and development, cell apoptosis and immune response. In general, activated STAT dimer binds to a palindromic sequence (TTCN2-4GAA) located at the upstream promoter region to activate gene transcription. Some signal pathways including Toll and Imd in silkworm Bombyx mori, a model of Lepidopteran insect, have been well studied. However, little is known regarding JAK-STAT signal pathway. In the present study, the genes regulated by JAK-STAT signal pathway were predicted by bioinformatics analysis. 1000bp of upstream promoter sequence of the all predicted genes were downloaded from the silkworm genome database, and the STAT binding sequence TTCN2-4GAA were searched by scanning the promoter sequences, the results showed that 1 to 6 the target sequences could be found in the upstream promoter sequences of 9293 genes coding7271 non-redundant proteins. Go annotation results showed that these proteins were involved to cellular component, molecular function and biological process, suggesting JAK-STAT pathway play an important role in many way. More than 50% genes related to binding, about 40% genes related to cellular process, metabolic process and catalytic activity in the targeting genes. It is considered that JAK-STAT play a role in immune response.1-4 STAT binding sequences could be detected in promoter region of some genes related to anti-viral factors, cellular immune effector, and small antimicrobial peptide including defensin, attacin, moricin and gloverin3, implying that the expression of some anti-viral factors, cellular immune effectors and antimicrobial peptides related to antiviral activity might be regulated by JAK-STAT signal pathway.

Hippo kinase cascade shared by a variety of multicellular animals is appreciated as a signaling pathway which aims to inhibit the growth of cells and it is very conservative during evolution. Recent studies have confirmed that the Hippo signal pathway functions in cancer, tissue regeneration as well as stem cell regulation. The silkworm Bombyx mori is a model of Lepidopteran insect, little is known regarding genes related to Hippo kinase cascade. In the present study, the sequences of major genes related to Hippo pathway are obtained successfully in silkworm, B. mori, by in silico cloning or RT-PCR, including BmHop, BmSav, BmMats, BmWts and BmYki. The deduced amino acid sequences of the genes were aligned with those of other species, although the sequence identities of these proteins from different species were not high, the conserved domains were prominent, suggesting that the roles of Hippo pathway in the silkworm are similar to those in other species. These results has laid an important foundation for the further understanding and clarifying the function of the Hippo signaling pathway in silkworm.

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