Gene Networks Database

Strongylocentrotus purpuratus Genes in Development: Primary mesenchyme- specific genes

msp130

Function

The msp130 gene codes for a primary mesenchyme lineage-specific cell surface protein in the embryo.
Experiments with the monoclonal antibodies suggested this protein to be a major cell surface antigen of primary mesenchyme cells (Anstrom et al., 1987).
The function of msp130 remains unclear, however it is evident that it has been implicated in major primary mesenchyme cell functions (Parr et al., 1989).
There is also some experimental evidence that msp130 may play a role in the entrance of calcium ions into the PMCs (Carson et al., 1985; Kabakoff et all., 1992).

Protein

The msp130 sequence predicts a protein of relative molecular weight 81000, which contrasts with the observed Mr = 130000 on standard polyacrilamide gel (Parr et al., 1990).
The msp130 protein possesses two novel glycine-rich domains and a signal peptide, but lacks a transmembrane domain.
Digestion of msp130 with endonuclease F reveals that this protein contains N-linked carbohtdrate groups.
msp130 is apparently a sulphated glycoprotein; two-dimensional immunoblots showed that msp130 is an acidic protein that becomes substantially less acidic in the absence of sulphate in the sea water (Anstrom et al., 1987).
The carboxyl-terminal sequence suggests that msp130 may be phosphatidylinositol-linked to the cell membrane and experiments with phospholipases support this conclusion (Parr et al., 1990).
SWISS_PROT: P08472

Subcellular location

Immunoelectron microscopy shows that msp130 is present on the trans side of the Golgi apparatus and extracellular surface of primary mesenchyme cells (Anstrom et al., 1987).

Expression Pattern

The transcript encoding msp130 is undetectable in egg RNA or 16-cell RNA (Leaf et al., 1987).
The msp130 transcripts are first detected at the blastula stage, in micromere-lineage cells just prior to ingression. Appearance of msp130 transcripts remains strictly limited to this lineage through the pluteus stage (Harkey et al., 1992).
The relative abundance of msp130 transcripts is uniform among the 32 cells of this lineage in secondary mesenchyme blastulae and in gastrulae. It indicates that expression is homogeneous among these cells up to the early prism stage. However, number of transcripts increases dramatically in the PMCs of an embryo during prism and pluteus stages, suggesting that these cells switch from an autonomous mode of regulation of the msp130 gene to an inductive mode.
In the pluteus larva, the highest levels of transcript expression occur in the cells associated with the rapidly growing tips of the spicular skeleton (Harkey et al.,1992).
The msp130 protein is first detectable soon after primary mesenchyme cell ingression into the blastocoel. It is present at the mesenchyme blastula, gastrula and pluteus stages (Leaf et al., 1987).

mRNA level

Temporal accumulation
Method: RNA gel blot hybridization
Reference: Leaf et al., 1987

Stage Egg 16-cell Premesenchyme blastula Mesenchyme blastula Gastrula Prism Pluteus Pluteus larva

Level - - + + + + + +

Spatial localization
Method: in situ hybridization
Reference: Harkey et al., 1992

Stage Egg 16-cell mesenchyme blastula Gastrula Prism Pluteus Pluteus larva

Tissue - - micromere-lineage cells prior to ingression PMC PMC PMC cells associated with the tips of the spicular skeleton