Purification and expression analysis of imaginal disc growth factor in the silkworm, Bombyx mori.
In the present study, we purified and sequenced a homolog of the Drosophila imaginal disc growth factor (IDGF) from the hemolymph of Bombyx mori (BmIDGF). Antibodies against BmIDGF were produced and subsequently used in immunoblotting analyses. The immunoblotting analyses demonstrated an extremely high level of BmIDGF in the hemolymph throughout the period of rapid growth of the organs of B. mori. The results of RT-PCR showed that BmIDGF was predominantly expressed in fat bodies. Real-time RT-PCR revealed that BmIDGF transcripts in fat bodies were highly expressed during the feeding stage but significantly suppressed during the molting, wandering, and pupal stages. Starvation brought about a significant decline of BmIDGF mRNAs in the fat bodies and BmIDGF proteins in the hemolymph. After re-feeding, the BmIDGF transcripts in fat bodies and BmIDGF proteins in the hemolymph increased again. In addition, an immunocytochemical study revealed BmIDGF proteins on the surface of wing discs. The present findings suggest that the level of BmIDGF in the hemolymph was modulated by the fat body in response to nutritional conditions and that BmIDGF was transported to target organs through the hemolymph.
Wang
Hua-Bing
HB
Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi, Japan.
Sakudoh
Takashi
T
Kawasaki
Hideki
H
Iwanaga
Masashi
M
Araki
Katsue
K
Fujimoto
Hirofumi
H
Takada
Naoko
N
Iwano
Hidetoshi
H
Tsuchida
Kozo
K
D000818:Animals; D012831:Bombyx / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005216:Fat Body / Q000378:metabolism; D005786:Gene Expression Regulation; D006458:Hemolymph / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data
D019476:Insect Proteins