J Biol Chem, Vol. 274, Issue 49, 35023-35028, December 3, 1999
Response to the Sexual Pheromone and Wounding in the Green
Alga Volvox: Induction of an Extracellular Glycoprotein
Consisting Almost Exclusively of Hydroxyproline
Frank
Ender,
Armin
Hallmann,
Peter
Amon, and
Manfred
Sumper
From the Lehrstuhl Biochemie I, Universität Regensburg,
Universitätsstrasse 31, D-93053 Regensburg, Germany
The extracellular matrix (ECM) of
Volvox is modified during development or in response to
external stimuli, like the sex-inducing pheromone. It has recently been
demonstrated that a number of genes triggered by the sex-inducing
pheromone are also inducible by wounding. By differential screening of
a cDNA library, a novel gene was identified that is transcribed in
response to the pheromone. Its gene product was characterized as an ECM
glycoprotein with a striking feature: it exhibits a hydroxyproline
content of 68% and therefore is an extreme member of the family of
hydroxyproline-rich glycoproteins (HRGPs). HRGPs are known as
constituents of higher plant ECMs and seem to function as structural
barriers in defense responses. The Volvox HRGP is also
found to be inducible by wounding. This indicates that the wound
response scenarios of higher plants and multicellular green algae may
be evolutionary related.
Copyright © 1999 by The American Society for Biochemistry and Molecular Biology, Inc.