ABSTRACT
We have developed two methods for the production of new biomaterials by using the silkworm Bombyx mori and the insect virus. 1) Proteins are expressed and simultaneously encapsulated into protein micro-crystals called polyhedra which are derived from cypovirus of the silkworm. The growth factors are stabilized by the encapsulation into micro-crystals, but they are gradually released from the micro-crystals during a culture with mammalian cells and direct the proliferation and differentiation. It is considered that the growth factor-encapsulated micro-crystals will enable new approaches for regenerative medicine. 2) We established transgenic silkworms with posterior silk glands (PSGs) that express the enzymatic domain of a 236cytotoxin, named pierisin-1A (P1A). P1A is an identified cytotoxic protein from the cabbage butterfly Pieris rapae, which has DNA ADP-ribosylating activity. In the later part of this chapter, we describe the biological property of the silkworms with the modified PSGs, which produced sericin cocoons with a potential utility in tissue engineering and a new approach involving targeted P1A expression that could be applicable to the development of biologically-useful model organisms with tissue-specific dysfunction.
