Program of the 2001 International Worm Meeting - Sternberg Lab ...

891
891. mab-21 expression is regulated
by genes controlling anesthetic
response.
Angus S.K. Leung, K. Wah Chu,
Stephen S.H. Ho, King L. Chow
Department of Biology, Hong Kong University
of Science and Technology, Clean Water Bay,
Kowloon , HONG KONG.
mab-21 gene encodes a novel protein that
determines cell fate and cell identity in male tail
development. Our previous study in Xenopus
indicated that inhibition of frog mab-21
homolog expression resulted in posterior body
patterning defect similar to that in embryos with
FGF signal depleted. This observation promoted
us to examine if mab-21 is acting in the FGF
pathway. Using a functional mab-21::gfp fusion
transgene as a reporter, we examine if the
expression and subcellular localization of the
protein is regulated by worm FGF components,
egl-17 and egl-15. It was noted that mutations in
these genes had no effect on mab-21 expression.
Instead, we observed as enhanced expression of
mab-21::gfp particularly in the hypodermal
tissue in unc-1 mutant, a linked mutation used in
this FGF pathway analysis.
The results suggest that strong expression of
mab-21::gfp transgene in hypodermis may be
related to the functional pathway that controls
sensitivity of C. elegans to volatile anaesthetic
chemicals. To ascertain such possibility, the
same reporter transgene was crossed into a
number of mutants known to be part of this
functional complex. Our result showed that the
mab-21::gfp expression was up-regulated in
unc-8 and mec-2 mutations, while it was
repressed by unc-24 and unc-79 mutations.
unc-1 encodes stomatin like protein and unc-8
belongs to the degenerin family. Both of these
genes code for integral membrane proteins,
arguing that MAB-21 expression level and its
function may be regulated by the signaling
process downstream of these membrane
proteins.
Since the reporter was a fusion protein, the
strong expression may be due to either enhanced
transcriptional activity or protein stability.
Experiments are underway to differentiate the
two possibilities and additional experiments
addressing the functional role between these
891
molecules as well as the biological significance
of such relationship will be presented.