Gene Networks Database
Paracentrotus lividus Genes in Development:
Butanol - extractable proteins
bep4 is a member of a multigenic family, coding for butanol-extractable proteins.
In sea urchin embryos butanol treatment extracts cell surface proteins including
the constituents of a 22S particle called toposome, which is believed
to play a role in cell interactions.
bep4 is a single-copy gene (Di Carlo et al., 1990).
bep4 is a butanol-extractable protein.
bep4 contain open reading frame coding for 307 amino acids.
Within the coding region there are two
domains (A and B) and one specific central
region. The A region code for 68 aa,
the B part contain 106 amino acids, the specific region can codify
for 95 amino acids.
By amino acid analysis it is possible to observe that
A and B regions are hydrophobic. Moreover,
the presence of two Cys in both of these regions allows to suppose
that the two parts might interact and build a highly
hydrophobic zone to be anchored at the plasma membrane
to the interaction between both parts (Di Carlo et al., 1990).
The deduced amino acid sequence contains two possible
Ca2+-binding motifs. The cluster of type
DXD(N)XD(N) is very frequent in many EF-hand domains (Tufty and Kretsinger, 1975).
This cluster is necessary for the coordination of Ca2+
ions by side chain oxygen atoms in the Ca2+- binding
sites. The aa of these motifs form a loop structure in which
the ligands residues are located (Tuffy and Kretsinger, 1975).
The possibility that the bep4 protein can bind Ca2+
may be important for its function, which has been demonstrated
to play a role in cell-cell interaction (Romancino et al., 1992).
bep4 presumably belongs to cell surface proteins (Di Carlo et al., 1990).
Northern blot analysis showed that bep4 is transcribed during oogenesis
into mRNA of 1.4 kb, which is stored in egg and utilized during
early embryogenesis. The highest intensity of the band is observed
in ovary and in egg RNA. The signal reduction is observed from 32 cell stage.
This RNA is not detectable after the gastrula stage (Di Carlo et al., 1990).
bep4 maternal messenger is localized in the animal part of P. lividus
egg and embryos. It was demonstrated that bep4 mRNA is associated with the
cytoskeleton element and that this association is necessary for the
localization (Romancino et al., unpublished results).
The spatial distribution of bep4 protein in eggs and embryos was established by whole mount
immunohistochemistry. This protein is located in the animal part of unfertilized and
fertilized eggs; thereafter it is much less represented in structures derived from the vegetal
cells of the embryo such as the micromeres of the 16 cell stage, the primary mesenchyme of
blastula and the gut of gastrula. At the prism stage bep4 protein is present to some
ectodermal parts and thereafter, at the pluteus stage, to the oral region (Romancino et al., 1998).
Method: Nothern blot analysis
Reference: Di Carlo et al., 1990
- bep4 Spherechinus granularis
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