Gene Networks Database

Lytechinus variegatus Genes in Development: Moesin

SUmoesin

Function

SUmoesin codes for the ezrin-radixin-moesin-like (ERM) molecule in the sea urchin. SUmoesin may be constitutively involved in interactions between the plasma membrane and the cytoskeleton (Bachman et al., 1995).

Protein

SUmoesin is a 75 kDa protein, the ERM family member. This protein contains an N-terminal region that is highly similar to ezrin/radixin/moesin from many species, while the divergent C terminus is most similar to moesin. SUmoesin lacks a polyproline stretch of amino acids that is found in ezrin and radixin. Amino acids predicted from the nucleotide sequence reveals four consensus tyrosine phosphorylation sites, two of which are shared by other ERM family members (Bachman et al., 1995).
SWISS_PROT: P52962

Subcellular location

Whole-mount indirect immunofluorescence imaging using confocal microscopy showed that in eggs, moesin is distributed in a punctate pattern throughout the cytoplasm. Within 10 minutes after fertilization, moesin becomes concentrated just beneath the plasma membrane in the egg cortex; over the same interval the punctate cytoplasmic distribution becomes less brightly fluorescent.
SUmoesin in embryos from 2-cell and early blastula stages is seen in the cell cortex in a predominately punctate distribution and continues to be seen in the cytoplasm at lower levels. The patchy staining on the surface of early embryos may correspond to the location of microvilli.
In the morula stage, moesin is localized at the cell cortex in the region of cell-cell contacts and on the apical sides of cells. There continues to be staining within the cytoplasm in a punctate pattern as well.
At hatched blastula, gastrula and feeding pluteus stages SUmoesin is concentrated in intercellular borders, and appears in the apical region where adherens junctions are known to be, and in the apical regions of cells.
In the pluteus larva, moesin is concentrated in the apical region of cell-cell contacts.
Apical localization of moesin is disrupted in the presence of reagents that prevent actin polymerization, but is unaffected in the presence of microtubule inhibitors such as colchicine. Moesin therefore requires an intact actin cytoskeleton to remain associated with the plasma membrane (Bachman et al., 1995).

Expression Pattern

The 6.3 kb message of SUmoesin is present in the ovary and abundant in the adult gut, but is absent in eggs. Moesin expression during embryogenesis begins at the late blastula stage and peaks at the pluteus larva stage. This developmental profile therefore is classified as an ëembryonic late geneí (Davidson, 1986).
Western blot hybridization showed that a 75 kDa protein is recognized at all stages of development from eggs through the 24 hour pluteus larva stage, and abundance is similar at each stage. The presence of moesin protein in eggs and during early embryogenesis indicates that moesin protein is provided maternally, because moesin RNA is absent from those early stages.
Immunoprecipitation of of SUmoesin from extracts of [35S]Met-Cys-labeled embryos showed that labeled moesin protein is not detected in early embryonic stages. Thus, zygotic SUmoesin is not translated until the blastula stage, after which it continues to be synthesized through the feeding pluteus larval stage.
Moesin protein is localized to the plasma membrane after fertilization and is associated with the region of cell-cell contacts in later embryogenesis.
At hatched blastula, gastrula and feeding pluteus stages SUmoesin is concentrated in intercellular borders and in the apical regions of cells in the ectoderm and endoderm. Moesin is not present in mesenchyme tissues.
In the pluteus larva, moesin is concentrated in the apical region of cell-cell contacts in the ectoderm, oral hood and mouth. Moesin staining is noticeably reduced in aboral and perianal ectoderm cells. In endoderm, moesin is concentrated at the apical surface of endoderm cells of the fore, mid-and hindgut (anus) regions (Bachman et al., 1995).

mRNA level

Temporal accumulation

Method: Nothern blot analysis
Reference: Bachman et al., 1995

Stage
Egg
Blastula
Mesenchyme blastula
Gastrula
Prism
Pluteus
Level
-
-
+ -
+
+
+ +

Protein level

Temporal accumulation

Method: Western blot analysis
Reference: Bachman et al., 1995

Stage
Egg
15 minutes
Blastula
Gastrula
Pluteus
Level
+
+
+
+
+

Protein level

Temporal accumulation

Method: Immunoprecipitation of of SUmoesin from extracts of [35S]Met-Cys-labeled embryos
Reference: Bachman et al., 1995

Stage
1 hour
Mesenchyme blastula
Level
-
+

Protein spatial localization

Method: Whole-mount indirect immunofluorescence imaging by confocal microscopy
Reference: Bachman et al., 1995

Stage
Egg
10 minutes after fertilization
2 cells and early blastula
Morula
Hatched blastula
Gastrula
Pluteus larva
Tissue
egg cytoplasm
beneath the plasma membrane in the egg cortex and in egg cytoplasm
whole embryo
whole embryo
Intercellular borders and the apical regions of cells in the ectoderm and endoderm
Intercellular borders, the apical regions of cells in the ectoderm and endoderm
Apical region of cell-cell contacts in the ectoderm, oral hood and mouth. Staining is noticeably reduced in aboral and perianal ectoderm cells. In endoderm SUmoesin is concentrated at the apical surface of cells of the fore, mid-and hindgut (anus) regions

Sequences

GenBank:

Regulatory Regions

Regulatory Connections

Upstream Genes

SUmoesin

Downstream Genes

Evolutionary Homologues

Links

Bibliography
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Comments are welcome to Sveta Surkova
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