Gene Networks Database

Hemicentrotus pulcherrimus Genes in Development: Primary mesenchyme-specific genes

HSM41

Function

HSM41 is a primary mesenchyme-specific gene, homologous to S. purpuratus SM50.
Like SM50 this gene encodes a protein of the matrix within which the mineral elements of the sceletal structures are embedded. HSM41 represents a single cDNA in Hemicentrotus pulcherrimus genome (Katoh-Fukui et al., 1992).

Protein

HSM41 is a spicule matrix protein.
The derived peptide sequence indicates a typical N-terminal signal peptide (von Heijne, 1983) and would have a relative molecular mass (Mr) of 41.000 after removal of signal peptide.
The amino acid sequence of HSM41 contains a tandemly repeated element of 13 amino acids. It has a consensus sequence of QPGFGNQPG(V/M)GG(R/Q/N). A hydropathy profile of the predicted protein shows that the repeated region is predominantly composed of hydrophylic amino acids while the N-terminal region is highly hydrophobic. As in SM50 and in LSM34, a proline-rich region was also detected upstream to the repeated region of the HSM41 protein (Katoh-Fukui et al., 1992).
SWISS_PROT: Q26264

Subcellular location

Expression Pattern

Nothern blot analysis detected no message in unfertilized eggs, cleavage stage embryos or early blastulae. In contrast, an intense signal of 1.9 kb appeared at the gastrula stage 24 h after fertilization, and the signal intensity, hence the mRNA concentration, did not change appreciably thereafter through the pluteus stage. A faint signal was observed in mesenchyme blastula.
In situ hybridization with the anti-sense pHPSMC probe revealed strong signals localized over the primary mesenchyme cells. The hybridization signal in other parts of the embryo was at background level.
Western blots detected a polypeptide of Mr~ 40.000 that is present in prism stage embryos but not in unfertilized eggs. Staining of pluteus larvae revealed immunoreactivity associated with the spicules (Katoh-Fukui et al., 1992).

mRNA level

Temporal accumulation

Method: Nothern blot analysis
Reference: Katoh-Fukui et al., 1992
Stage
Egg
Cleavage
Blastula
Gastrula
Prism
Pluteus
Level
-
-
-
+ +
+ +
+ +

mRNA Spatial localization

Method: In situ hybridization
Reference: Katoh-Fukui et al., 1992

Stage
Gastrula
Tissue
Strong signals localized over the primary mesenchyme cells. The hybridization signal in other parts of the embryo was at background level

Protein spatial localization

Method: Immunocytochemical staining
Reference: Katoh-Fukui et al., 1992

Stage
Pluteus
Tissue
Immunoreactivity is associated with spicules

Ectopic expression

Expression in isolated and cultured blastomeres

When the expression of HSM41 mRNA was examined in isolated blastomeres, no HSM41 mRNA was detectable in micromeres or in a combined fraction of mesomeres and macromeres immediately after isolation.
After 48 h of culture, the descendants of micromeres began to form spicules, and concomitantly a strong signal was detected in micromeres. These observations suggest that HSM41 mRNA is expressed specifically in isolated and cultured micromeres that are actively forming spicules, and they are consistent with the idea that HSM41 mRNA is involved in spiculogenesis (Katoh-Fukui et al., 1992).

Expression of pHPSMC mRNA in isolated and cultured blastomeres

Method: Nothern blot analysis
Reference: Katoh-Fukui et al., 1992
Stage/fraction
micromeres
mesomeres+macromeres
16 cells
-
-
Cultured, 48 hr *
+ +
- - +

* A signal of much weaker intensity (approximately 1/6) was also detected in cultured mesomeres and macromeres. The latter signal may have resulted from contamination of this fraction by micromeres at the time of isolation, or from trans-differentiation of macromeres into spicule-forming cells.

Sequences

GenBank:

Regulatory Regions

Regulatory Connections

Upstream Genes

HSM41

Downstream Genes

Evolutionary Homologues

Links

Bibliography
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Comments are welcome to Sveta Surkova
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