The present invention relates to a nucleic acid for vaccine that has undergone codon optimization for expression in Bombyx mori, a vector comprising the nucleic acid, Bombyx mori comprising the vector, and a method for producing a vaccine in which they are used.

Disclosed are methods, compositions, and systems for transforming silkworms to produce spider silk and analogs of spider silk. In certain embodiments, the method may include inserting a DNA sequence coding for at least a portion of a spider silk fibroin polypeptide, or an analog of a spider silk fibroin polypeptide, positioned between at least a portion of the 5 and 3 ends of a silkworm fibroin gene to generate a fusion gene construct having a sequence that encodes for a polypeptide comprising both spider silk fibroin and silkworm silk fibroin sequences. In certain embodiments, the fused gene is able to replace a native gene present in the silkworm such that the transformed silkworm expresses a polypeptide comprising a spider silk fibroin polypeptide, or an analog thereof, and expresses significantly less of the native silkworm silk.

Disclosed are methods, compositions, and systems for transforming silkworms to produce spider silk and analogs of spider silk. In certain embodiments, the method may include inserting a DNA sequence coding for at least a portion of a spider silk fibroin polypeptide, or an analog of a spider silk fibroin polypeptide, positioned between at least a portion of the 5 and 3 ends of a silkworm fibroin gene to generate a fusion gene construct having a sequence that encodes for a polypeptide comprising both spider silk fibroin and silkworm silk fibroin sequences. In certain embodiments, the fused gene is able to replace a native gene present in the silkworm such that the transformed silkworm expresses a polypeptide comprising a spider silk fibroin polypeptide, or an analog thereof, and expresses significantly less of the native silkworm silk.