regulation of cuticle formation and chitin synthesis
A. Retnakaran 1, W.
Tomkins 1, M. Primavera 1, T. Ladd 1, Q.-L. Feng 1, B. M. Arif 1
and S.R. Palli 1,2
1 Great Lakes Forestry Centre, Canadian Forest Service, P.O.
Box 490, Sault Ste. Marie, Ontario, Canada, P6A 5M7; 2 Rohm and
Haas Research Laboratories, 727 Norristown Road, Spring House,
Penn., 19477, USA
chitin synthesis and endocuticular elaboration occur during the
inter-molt period early in each stadium prior to the appearance of
the ecdysone peak in the hemolymph. The formation of the cuticulin
layer, dense epicuticle and the secretion of the molting fluid are
up-regulated by ecdysone whereas sclerotization, chitin synthesis,
endocuticular elaboration and ecdysis are down-regulated by this
hormone. Juvenile hormone modulates the effects of ecdysone and
alteration of its titer leads to phenotypic changes in the
cuticle. Structural and sclerotization genes such as LCP-14 and
DDC are expressed in the absence of ecdysone whereas molt genes
such as the transcription factors E75 and CHR3 that transactivate
genes responsible for the molting fluid, cuticulin, epicuticle and
ecdysis are expressed in the presence of ecdysone. Elucidation of
the molecular regulatory mechanism and ultrastuctural changes in
cuticle morphogenesis using a non-steroidal ecdysone agonist,
RH-5992, in the spruce budworm, Choristoneura fumiferana,
will be described.
Cuticle, Chitin, Ecdysone, Sclerotization, Juvenile hormone,
Transcription factors, RH-5992, Choristoneura fumiferana
Copyright: Session 13 – INSECT
PHISIOLOGY, NEUROSCIENCES, IMMUNITY AND CELL BIOLOGY Symposium
and Poster Session, ABSTRACT BOOK II – XXI-International
Congress of Entomology, Brazil, August 20-26, 2000.