National Institute of Agrobiological Sciences

Nitto Boseki Co., Ltd.

Toshiki Tamura

Isao Kobayashi

Hideki Sezutsu

Keiro Uchino

Iwao Kiyokawa

Toshihide Miura

Katsuhiro Katayama

Ryo Kojima

Tatsuya Ohashi

Yuji Arimatsu

Toshio Kanda

Katsura Kojima

Hisae Arai

Noriyuki Funahashi

Pentameric CRP is produced at a high efficiency by transferring DNA, which encodes monomeric CRP, into a silkworm to thereby construct a transgenic silkworm and then collecting and purifying pentameric CRP that is produced by the transgenic silkworm constructed above.

DNA encoding canine monomeric CRP and expression vector containing the DNA

The present inventors produced transgenic silkworms which comprise a promoter of a DNA encoding a protein specifically expressed in the silk gland and a DNA encoding a recombinant antibody whose expression is regulated directly or indirectly by the promoter, and which secrete the recombinant antibody into the silk gland. The recombinant antibodies produced from the silk gland of the transgenic silkworms were confirmed to be active.

Antibody-producing transgenic silkworms and methods for producing the same

Pentameric CRP-producing transgenic silkworm

Silkworms which have (i) a DNA encoding a transcriptional regulator operably linked downstream of a promoter of a DNA encoding a protein specifically expressed in the silk gland and (ii) a DNA encoding TRACP5 operably linked downstream of a target promoter of the transcriptional regulator were produced. The result showed that active TRACP5b was produced from the silkworms. This means that TRACP5 produced from the silk gland of the silkworms undergoes processing in the silk gland that is similar to the processing taking place at bone resorption sites.

Method for production of TRACP5b

Transgenic silkworms comprising GFP whose expression is regulated by the sericin gene promoter were produced. Observation of the silk glands of the last instar larvae of the silkworms showed fluorescence only in the middle silk glands. GFP was secreted from middle silkgland cells from around the spinning stage, indicating that GFP moved into the gland lumen. Finally, GFP was spun into cocoon filaments, and cocoons containing large amounts of GFP were produced. Thus, by using the promoter region of the sericin gene, recombinant proteins can be produced in the middle silk glands. Furthermore, the recombinant proteins produced in the middle silk glands were readily secreted into the lumen of the middle silk glands.

Methods for producing proteins using silkworm middle silk gland-specific gene expression system

Growing community of inventors

Tsukuba, Japan

Toshiki Tamura