Bombyxin is a growth factor for wing imaginal disks in Lepidoptera.

Journal Article

The mechanisms that control the growth rate of internal tissues during postembryonic development are poorly understood. In insects, the growth rate of imaginal disks varies with nutrition and keeps pace with variation in somatic growth. We describe here a mechanism by which the growth of wing imaginal disks is controlled. When wing imaginal disks of the butterfly Precis coenia are removed from the larva and placed in a standard nutrient-rich tissue culture medium they stop growing, suggesting that nutrients alone are not sufficient to support normal growth. Such disks can be made to grow at a normal rate by supplementing the culture medium with an optimal concentration of the steroid hormone 20-hydroxyecdysone and with hemolymph taken from growing larvae. The growth-promoting activity of the hemolymph is caused by a heat-stable factor that can be extracted from the CNS and appears to be identical to the neurohormone bombyxin, a member of the insulin family of proteins. Synthetic bombyxin stimulates growth at concentrations as low as 30 ngml, and specific antibodies to bombyxin completely remove growth-promoting activity from the hemolymph. Bombyxin evidently acts together with 20-hydroxyecdysone to stimulate cell division and growth of wing imaginal disks. It appears that the level of bombyxin in the hemolymph is modulated by the brain in response to variation in nutrition and is part of the mechanism that coordinates the growth of internal organs with overall somatic growth.

Full Text

Duke Authors

Cited Authors

  • Nijhout, HF; Grunert, LW

Published Date

  • November 26, 2002

Published In

Volume / Issue

  • 99 / 24

Start / End Page

  • 15446 - 15450

PubMed ID

  • 12429853

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.242548399

Language

  • eng

Conference Location

  • United States