MbIDGF, a novel member of the imaginal disc growth factor family in Mamestra brassicae, stimulates cell proliferation in two lepidopteran cell lines without insulin.
Imaginal disc growth factor (IDGF) is a soluble polypeptide growth factor that was first identified from the conditioned medium of Drosophilia imaginal disc C1.8+ cells. Working with insulin, IDGF stimulated the growth of cultured imaginal disk cells, which suggested that IDGF might function as a cofactor of Drosophila insulin or insulin like peptide. Here we report a new member of the IDGF family, named MbIDGF, from the cabbage armyworm, Mamestra brassicae. Using a cloned cDNA of MbIDGF, recombinant MbIDGF protein was expressed in baculovirus-infected Sf9 cells and purified. Without insulin, the recombinant MbIDGF protein stimulated cell growth of SES-MaBr-4 and NIAS-MaBr-93 cell lines that were derived from the fat bodies and hemocytes of M. brassicae, in a dose-dependent manner. The saturation of growth stimulation by MbIDGF was attained for the two types of cells at 80 ng/ml (0.8 nM) and 300 ng/ml (6 nM), respectively. The results suggest that MbIDGF may stimulate the growth of lepidopteran cells by a new mechanism without associating with the insulin pathway.
Zhang
Jun
J
Division of Biofunctional Science, Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan.
Iwai
Sachio
S
Tsugehara
Taketo
T
Takeda
Makio
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004305:Dose-Response Relationship, Drug; D006133:Growth Substances / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D007328:Insulin / Q000494:pharmacology*; D007915:Lepidoptera / Q000166:cytology*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D017931:DNA Primers; D018076:DNA, Complementary; D006133:Growth Substances; D007328:Insulin; D011994:Recombinant Proteins