COLL1-alpha

Function

COLL1-alpha encodes collagen which belongs to the fibril-forming group (D'Alessio et al., 1989). Collagens play a role in determining matrix composition and, consequently, in influecing the processes of spiculogenesis and gastrulation (Wessel et al., 1987, Blankenship, et al., 1984).

Protein

COLL1-alpha is a fibrillar collagen.
The 5` overlapping sequences of COLL1-alpha cDNAs (Uni 11 and Uni 54) code for two distinct domains of the polypeptide, namely, a 252-amino acid, cysteine-rich carboxyl polypeptide and an uninterrupted 478-amino acid helical domain.
Examination of the deduced amino acid sequences revealed a variety of structural features characteristic of fibril-forming collages. In the helical domain they include the tetrapeptide Lys-Gly-His-Thr, likely to represent a substrate for lysine-mediated crosslinking of the fibrils, and at its carboxyl terminus several Gly-Pro-Pro triplets conceivably involved in the stabilization of the trimer. The 26-amino acid carboxyl telopeptide contains a third structural feature- the crosslinking lysine residue.
Analogy with vertebrate fibrillar collagens is apparent when a selected portion of the sea urchin carboxyl propeptide is aligned with those human chains (COL2A1, COL1A1 and COL3A1). In this region there is a remarkable conservation in the spatial architecture and to some extent, the sequence context around the cysteinyl residues involved in the association and alignment of individual procollagen chains before triple helix formation (D'Alessio et al., 1989).
GenBank: 159958

Subcellular location

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

Expression Pattern

The COLL1-alpha mRNA, approximately 6 kb in size, is clearly detected in prism-stage embryos and significantly accumulates until the free swimming/feeding pluteus larval stage. Nothern blot analysis also detected a weaker band in RNA from gastrulae.

mRNA level

Temporal accumulation
Method: Northern blot analysis
Reference: D'Alessio et al., 1989

Stage Gastrula Prism Pluteus

Level + - + +

COLL1-alpha transcripts were first detected by in situ hybridization in forming primary mesenchyme cells at the mesenchyme blastula stage.
In the late gastrula stage, the signal was increased relative to earlier stages over most, but not all primary mesenchyme cells. Conceivably, some of the mesenchyme cells exhibiting a background level of signal are actually pigment cells precursors. At this stage the forming secondary mesenchyme also appeared intensely labeled.
By the prism stage, while many of the primary mesenchyme cell derivatives produced a signal above background, the most heavily labeled cells were the derivatives of the secondary mesenchyme.

Spatial localization
Method: in situ hybridization
Reference: D'Alessio et al., 1989

Stage Early mesenchyme blastula Late gastrula Prism

Tissue Primary mesenchyme cells Primary and secondary mesenchyme cells Primary and secondary mesenchyme cells

Sequences

GenBank:

mRNA, 3' end

Regulatory Regions

Regions

Regulatory Connections

Upstream Genes

COLL1-alpha

Downstream Genes

Evolutionary Homologues

COL2A1 H. sapiens

COL1A1 H. sapiens

COL3A1 H. sapiens

COL1A2 H. sapiens

COL5A2 H. sapiens

COL11A1 H. sapiens

Links

Urchin Web

Bibliography

UrchiNet

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Stage	Early mesenchyme blastula	Late gastrula	Prism
Tissue	Primary mesenchyme cells	Primary and secondary mesenchyme cells	Primary and secondary mesenchyme cells