Gene Networks Database

Lytechinus pictus Genes in Development: Actins



LpC4 gene codes for the cytosceletal type actin (Fang et al., 1996). Actin represents one of the most abundunt and best characterized structural components in eucaryotic cells, involved in a wide variety of cytoskeletal, locomotive, and tension-generating functions (Davidson, 1989).
Each haploid L. pictus genome contains a single copy of each of the actin genes LpC1, LpC2, LpC3, LpC4, and LpM. Southern blot analysis of genomic DNA clones have detected no close linkage of L.pictus actin genes in contrast to the cytosceletal actins of S. purpuratus, which are clustered into two linkage groups of related genes (Fang et al., 1996).
The LpC4 actin gene may serve as a marker of of the primary mesenchyme cells as they begin actively engage in sceletogenesis (Fang et al., 1996).


LpC4 protein belongs to a family of the cytoskeletal actins (Fang et al., 1996).

Subcellular location


Expression Pattern

The LpC3 and LpC4 transcripts showed similar temporal patterns of accumulation and are much more less abundant than the LpC1 and LpC2 mRNAs. The transcripts are not detected until the mesenchyme blastula stage. The level of transcripts increase during gastrulation and remains constant through the prefeeding pluteus stage
The LpC4 actin gene is preferentially expressed in the primary mesenchyme cells (PMCs) at gastrula and pluteus stages. It is also detected in some secondary mesenchyme cells (SMCs) at pluteus stage. LpC4 actin transcripts were first detected in clusters of PMCs ventrolaterally located at the positions where the two aboral arms will later protrude. More PMCs were stained in plutei. Some cells embedded in the ectodermal wall, presumably the pigment cells, were lightly stained in the late gastrula embryo. Although LpC4 mRNA can be detected by Nothern blots at the mesenchyme blastula stage, it was not detected until gastrula by whole mount in situ hybridization. LpC4 mRNA may be present in low levels in many cells at mesenchyme blastula stage, making them difficult to detect (Fang et al., 1996).

mRNA level

Temporal accumulation

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

Mesenchyme blastula

Spatial localization

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

Late gastrula
PMCs, some cells embedded in the ectodermal wall, presumably the pigment cells (lightly stained)
PMCs, some SMCs (presumably the pigment cells)



Regulatory Regions

Regulatory Connections

Upstream Genes


Downstream Genes

Evolutionary homologues

  • CyI Strongylocentrotus purpuratus
  • CyIIa Strongylocentrotus purpuratus
  • CyIIb Strongylocentrotus purpuratus
  • CyIIIa Strongylocentrotus purpuratus
  • CyIIIb Strongylocentrotus purpuratus
  • M actin Strongylocentrotus purpuratus
  • LpC2 Lytechinus pictus
  • LpC3 Lytechinus pictus
  • LpC1 Lytechinus pictus
  • LpM Lytechinus pictus
  • Sf15a S. franciscanus
  • Sf15b S. franciscanus
  • PoCy P. ochraceus
  • PoM P. ochraceus
  • LpC4 homologue of Lytechinus variegatus



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