Gene Networks Database
Hemicentrotus pulcherrimus Genes in Development: forkhead- related genes
Hphnf3 is a sea urchin member of the forkhead- related gene family.
All members of this family share a conserved, 110 bp- long DNA binding motif,
the forkhead domain. According to sequence similarities Sasaki and Hogan (1993)
subdivided these genes into at least four classes.
A more recent analysis by Kaufmann and Knochel (1996) subdivided these genes into
ten distinct classes. Hphnf3 belongs to the class I subfamily
of Sasaki and Hogan (1993), and to class 1a of Kaufmann and Knochel (1996),
as does the mouse HNF-3b.
In contrast, S. purpuratus forkhead-homologue belongs to
the class IV subfamily Sasaki and Hogan (1993).
Hphnf3 may contribute to specification of archenteron cells.
This gene is present as a single copy per haploid genome (Harada et al., 1996).
Hphnf3 open reading frame predicts a polypeptide of 381 amino acids. The calculated
relative molecular mass of this protein is 42*103 kDa (Harada et al., 1996).
Nothern blot analysis showed that the Hphnf3 transcripts are undetectable in unfertilized eggs
and the embryos at the cleavage and early blastula
stages. A distinct band, about 3.0 kb in length, was first detected in hatched blastulae.
The transcripts accumulated to maximal extents at the gastrula and prism stages.
The band was detectable at pluteus larva stage, although it was much less intense.
The pattern of Hphnf3 expression resembles the transient expression of the mouse HNF-3b,a genes
in the embryo.
In situ hybridization revealed that in hatching blastula the signal is strongest in the
cells of the vegetal region. At mesenchyme blastula intence staining is observed at the vegetal plate.
At the early gastrula stage when the archenteron begins to invaginate the cells surrounding the
blastopore stain intensely, while there is less hybridization in the invaginating
archenteron per se. At the late gastrula stage intence hybridization is evident
in the cells of the hindgut. In addition, the midgut and foregut regions
of the archenteron also show strong staining.
At the prism stage, the difference in expression level between the non-invaginating
vegetal region and the invaginating archenteron becomes less evident.
Hybridization can be detected evenly throughout the archenteron.
As development proceeds the level of transcript declines so that no staining
above the background level can be observed at the pluteus larva stage (Harada et al., 1996)
Method: Nothern blot hybridization
Reference: Harada et al., 1996
Method: Whole mount in situ hybridization
Reference: Harada et al., 1996
||Cells of the vegetal region
||Cells of the vegetal plate
||Bottom of invaginating archenteron
||Cells, surrounding the blastopore (intence signals), invaginating archenteron (weak signals)
||Blastopore and archenteron (hindgut, midgut and foregut)
||Difference in expression level between the non-invaginating
vegetal region and the invaginating archenteron becomes less evident, hybridization can be
detected evenly throughout archenteron
||No staining above the background level
- HNF-3b mouse (Mouse Genome Informatics)
- forkhead Drosophila (Interactive Fly)
- Axial Zebrafish
- HNF-3b Xenopus
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