Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 2004
Publication Date: July 1, 2004
Citation: Blackburn, M.B., Loeb, M.J., Clark, E.A., Jaffe, H. 2004. Stimulation of midgut stem cell proliferation by manduca sexta arylphorin. Archives of Insect Biochemistry and Physiology. Vol# 55 Pg. 26-32
Interpretive Summary: Artificially cultured insect midgut cells may prove to be a valuable tool in developing assays for the screening of insecticidal compounds, as well as for understanding the physiology of these important cells. However, there is little information available regarding the factors that control the growth and development of these cells. Such information is of critical importance if normally functioning cells are to be maintained in artificial culture. We have discovered that a storage protein called alpha-arylphorin, present in fat tissues of the tobacco hornworm, stimulates the proliferation of midgut stem cells from the tobacco budworm in culture. These stem cells are the progenitor cells that develop into mature gut cells. This discovery should be of interest to scientists conducting basic research on insect gut physiology, and to those studying the interactions of pathogens or toxins within the insect gut.
Extracts of the green-colored perivisceral fat body of newly ecdysed Manduca sexta pupae stimulate mitosis in midgut stem cells of Heliothis virescens cultured in vitro. Using a combination of
cation- and anion-exchange chromatography, we have isolated a protein from these fat body extracts that accounts for the observed stem cell proliferation. SDS-PAGE analysis of the protein results in a single band of 77 kDa. Sequences of tryptic peptides from this protein are identical to internal sequences of the storage hexamer a-arylphorin. The a-arylphorin isolated by our procedure represents a small fraction of the total arylphorin present in the fat body extract. However, it alone seems responsible for the stimulation of mitotic activity in H. virescens midgut stem cells.