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).

Subcellular location

Expression Pattern

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)

mRNA level

Temporal accumulation

Method: Nothern blot hybridization
Reference: Harada et al., 1996

Unfertilized egg
16 cells
Early blastula
Hatching blastula
Mesenchymal blastula
Pluteus larvae
+ +
+ +
+ -

Spatial localization

Method: Whole mount in situ hybridization
Reference: Harada et al., 1996

Hatching blastula
Mesenchyme blastula
Early gastrula
Late gasrula
Pluteus larvae
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


Regulatory Regions

Regulatory Connections

Upstream Genes


Downstream Genes

Evolutionary Homologues



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