Hpcol1

Function

Hpcol1 codes for a fibrillar collagen. Collagen family in sea urchin embryos functions primarily in spiculogenesis (Tomita et al., 1994).

Protein

Epitope selection of the antibodies with the HpCol1 beta-galactosidase fusion protein revealed that the HpCol1 cDNA encodes the alpha120 and alpha140 chains of H. pulcherrimus collagen.
The cloned region of Hpcol1 mRNA sequence encodes a part of collagen triple helical domain composed of uninterrupted Gly-Xaa-Yaa triplets (378 amino acids) and the carbohyl-proximal sequences including carboxyl telopeptide (28 amino acids) and carboxyl propeptide (225 amino acids). This structure is characteristic for fibril-forming collagens.
The triple helical domain is rich in proline and five Gly-Pro-Pro triplets occur at its carboxyl-terminus. This domain also contains a Lys-Gly-His-Pro sequence which is likely to be responsible for lysine-mediated cross-linking of the fibrills.
Cystein rich carbohyl propeptide is also deduced from the Hpcol1 sequence. Assuming that the carboxyl-proteinase cleavage takes place at the site predicted for the vertebrate collagens (Dion and Myers, 1987), carboxyltelopeptide of 28 amino acid residues remains after fibril-formation. This region contains a lysine residue which should participate in covalent cross-linking.
Collagen isolated from H. pulcherrimus contains two major alpha-chains and a minor component with molecular weights 120 000, 90 000 and 140 000. These collagen chains are denoted as alpha120, alpha90 and alpha140, respectively. Alpha120 chain of H. pulcherrimus collagen is rich in carbohydrates (Tomita et al., 1994).
GenBank: 545688

Subcellular location

Collagen molecules are found in the intercellular spaces (Baccetti et al., 1985).

Expression Pattern

Nothern blot analysis shows that a small amount of Hpcol1 6 kb mRNA is present in embryos at the prism stage. Transcripts of the same size are present in adult test.
However, Hpcol1 mRNA was not detectable in embryos at stages preceding prism. This shows that Hpcol1 mRNA is expressed in embryos as early as the prism stage.
Immunofluorescence staining of whole mount pluteus embryos detected positive signals around spicules and in the coelom in the form of meshwork (Tomita et al., 1994).

mRNA level

Temporal accumulation
Method: Nothern blot analysis
Reference: Tomita et al., 1994

Stage 32 cells Hatching blastula Mesenchyme blastula Late gastrula Prism

Level - - - - +

Spatial localization
Method: Immunofluorescence staining of whole mount pluteus embryos, using anti-denatured sea urchin collagen antibodies
Reference: Tomita et al., 1994

Stage Pluteus

Tissue Positive signals are detected around spicules and in the coelom in the form of meshwork