Gene Networks Database
Genes in Development: beta-1,3 glucanase
In the animal kingdom, the known distribution of beta-1,3
glucanases is restricted to the eggs and digestive tract of
echinoderms. The enzymes in these two cell types are of the
same molecular weight and are antigenically similar. In the
gut, the enzyme is presumed to catalyze the degradation of
ingested algal beta-glucans.
Why beta-1,3 glucanase is in sea urchin
eggs and is released at fertilization remains unclear. The
enzyme is exocytosed from cortical granules 30 sec after
fertilization, and active enzyme can be recovered from both
young embryos and the perivitelline space surrounding the
embryo. All but one of 13 species of sea urchin studied
have beta-1,3 glucanase stored in cortical granules in unfertilized
eggs. Nevertheless, its endogenous substrate and function
are unknown (Bachman et al., 1996).
The start methionine of the deduced protein is followed by a
hydrophobic stretch of 20 aa that is presumed to be the signal
sequence. This stretch terminates with a glutamine,
which is the presumed V8 protease cleavage site.
The mature protein is 499 aa, with
a predicted Mr of 57 and pI of 4.1 (Bachman et al., 1996).
The enzyme is exocytosed at
fertilization and it persists in the perivitelline space
until hatching (Bachman et al., 1996).
Nothern blot analysis recognized a message of 3.2 kb in eggs of L. variegatus
and a slightly larger RNA was detected in the adult gut.
The beta-1,3 glucanase protein was followed during
early sea urchin development by Western blot analysis using a
polyclonal antibody made to the native enzyme.
A single 68-kDa protein is present during early
embryogenesis in L. variegatus. By 72 hr, the embryos are
actively feeding and the enzyme reappears in the gut as
revealed by immunofluorescence and by Western blot analyses (Bachman et al., 1996).
Method: Western blot analysis
Reference: Bachman et al., 1996
- Bacillus circulans beta-1,3 glucanase
- Horseshoe crab (Tachypleus) clotting factor
- Rhodothermus marinus beta-1,3 glucanase
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