Worm Breeder's Gazette 14(2): 46 (February 1, 1996)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

tollish genes in C. elegans

Alyce L. Finelli, Cathy Savage, Seo-Hee Cho, Richard W. Padgett.

Waksman Institute, Rutgers University, Piscataway, NJ 08855

        Members of the tolloid/BMP-1 family of astacin zinc binding
metalloproteases have been shown to be involved in the activation of
extracellular growth factors, thus regulating various developmental
events. The Drosophila tolloid gene genetically interacts with
decapentaplegic (dpp), a member of the TGF-b-like family of growth
factors, and is strongly implicated in enhancing its activity. The sea
urchin tolloid/BMP-1 member, SpAN, is expressed temporally and spatially
with univin, a TGF-b-like member, suggesting these two proteins may
interact. Human BMP-1 has been copurified with other TGF-b-like BMPs,
suggesting that these metalloproteases form complexes with the growth

        tolloid/BMP-1 subfamily members contain one or more EGF and CUB
(found in the complement proteins C1r and C1s) repeats C-terminal to the
protease domain. These motifs, which vary in order and number between
members, are strongly implicated in protein-protein interactions,
allowing the specific recognition of different growth factors. We have
previously characterized the two known members in C. elegans, tollish-1
(T24A11) and tollish-2 (R151). Both genes have an EGF and a CUB repeat
following the metalloprotease domain. tollish-2 is unique among members
in that it contains a thrombospondin (TSP) repeat, found in the
extracellular matrix protein thrombospondin.

        We would like to determine the function of the tollish-1 and 2
genes, particularly their involvement with the processing and/ or
activation of C. elegans growth factors. While we are searching for
mutations, antisense RNA injections will be done in an attempt to obtain
a phenotype. LacZ constructs to study the expression patterns of toh-1
and toh-2 are also being made.

        In addition to the tollish genes, there exists a handful of zinc
metalloproteases recently identified by the genome sequencing
consortium. We are currently analyzing the relationships of these
metalloproteases via sequence comparison with other members. Two of the
sequences analyzed from cosmids C05D11 and C07D10 are most closely
related to HCE and LCE, hatching enzymes from the teleost Oryzias
latipes. toh-2 and sequences from cosmid K04E7 are most closely related
to SpAN and BP10, which are expressed in very early blastula stages of
the sea urchin and have been suggested to play a role in differentiation
and patterning of the embryo. We plan to characterize the gene encoded
by K04E7, as well as other genes on cosmids which show a close
relationship to tolloid/BMP-1 members, to determine their developmental
roles in C. elegans.