LvN1.2

Function

LvN1.2 is an endoderm-specific gene (Wessel et al., 1989).

Protein

LvN1.2 is a 25-kDa protein. The sequence of this protein does not correspond to any known amino acid sequences (Wessel et al., 1989).
SWISS_PROT: P15262

Subcellular location

Immunofluorescence analysis showed that the LvN1.2 protein is present in distinct cytoplasmic particles concentrated to the apical aspect of the hindgut and midgut cells (Wessel et al., 1989).

Expression Pattern

Nothern blot analysis revealed that the LvN1.2 transcript is first detectable at the mesenchyme blastula stage and accumulates from gastrulation to the pluteus larval stage approximately 15-fold. The 1.2-kb transcript is not detected in eggs or during early embryogenesis up to the mesenchyme blastula stage.
In situ hybridization analysis detected no LvN1.2 transcripts at the mesenchyme blastula stage, or at any earlier developmental stage. Early in gastrulation (primary invagination) the hybridization signal is present throughout the invaginating archenteron, but not in mesenchyme cells delaminating from this region.
At the late gastrula embryo regions of presumptive hindgut-midgut are distinguished from the presumptive foregut by differential LvN1.2 hybridization, through the boundary separating these regions is not as distinct as in older embryos.
In situ hybridization of pluteus stage embryos demonstrated that the endodermal cells of the midgut and hindgut contain similar levels of hybridization signal, but cells of the foregut do not contain any signal above background. A sharp boundary exists between cells of the midgut, which contain maximum hybridization signal, and cells of the foregut, which contain only background levels of the signal. This boundary, which is also present between cells of the hindgut and the adjacent anal ectoderm, is 1-2 cells wide.
When embryos of different developmental stages were probed with antibodies to LvN1.2 protein by Western blots, the 25-kDa protein was first detected in late gastrulae, approximately 4 hr after the first detectable signal of LvN1.2 mRNA by Nothern blot analysis. The intensity of the signal increases through development from prism to the pluteus stage.
Immunofluorescence analysis showed that at late gastrula the LvN1.2 protein is detectable at low levels in presumptive midgut and hindgut. At the pluteus stage this protein is present in the midgut and hindgut (Wessel et al., 1989).

mRNA level

Temporal accumulation
Method: Nothern blot hybridization
Reference: Wessel et al., 1989

Stage Egg Cleavage Blastula Mesenchyme blastula Early gastrula Late gastrula Prism Pluteus

Level - - - + + + + + + +

mRNA spatial localization
Method: Whole mount in situ hybridization
Reference: Wessel et al., 1989

Stage Mesenchyme blastula Early gastrula Late gastrula Prism Pluteus

Tissue - throughout the invaginating archenteron regions of presumptive hindgut-midgut regions of presumptive hindgut-midgut endodermal cells of the midgut and hindgut