Transgenic silkworms producing sericin cocoons applicable for tissue engineering

Specific gene functions have been successfully suppressed by gene silencing or editing in many organisms. However, genetic manipulation to suppress the function of a target tissue has not been achieved using genes such as cytotoxin family members. We established transgenic silkworms with posterior silk glands (PSGs) that express the enzymatic domain of the cytotoxin pierisin-1A (P1A), a recently identified cytotoxic protein from the cabbage butterfly Pieris rapae, which has a relatively lower DNA ADP-ribosylating activity among the pierisin family. Larvae with the modified PSGs produced sericin cocoons with potential utility in tissue engineering. Our observations of an embryonic stem (ES) cell proliferation on fabricated sericin hydrogels demonstrated that such gels can act as scaffolds to support cell growth and also mimic extracellular matrices to provide cell growth factors. In this highlight paper, we describe a new approach through targeted P1A expression, which could be applicable to the development of biologically-useful model organisms with tissue-specific dysfunction.