T-brain homologue (HpTb) is involved in the archenteron induction signals of micromere descendant cells in the sea urchin embryo

Signals from micromere descendants play a crucial role in sea urchin development. In this study, we demonstrate that these micromere descendants express HpTb, a T-brain homolog of Hemicentrotus pulcherrimus. HpTb is expressed transiently from the hatched blastula stage through the mesenchyme blastula stage to the gastrula stage. By a combination of embryo microsurgery and antisense morpholino experiments, we show that HpTb is involved in the production of archenteron induction signals. However, HpTb is not involved in the production of signals responsible for the specification of secondary mesenchyme cells, the initial specification of primary mesenchyme cells, or the specification of endoderm.HpTb expression is controlled by nuclear localization ofβ-catenin, suggesting that HpTb is in a downstream component of the Wnt signaling cascade. We also propose the possibility that HpTbis involved in the cascade responsible for the production of signals required for the spicule formation as well as signals from the vegetal hemisphere required for the differentiation of aboral ectoderm.

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A large-scale analysis of mRNAs expressed by primary mesenchyme cells of the sea urchin embryo

Development ◽

10.1242/dev.128.13.2615 ◽

2001 ◽

Vol 128 (13) ◽

pp. 2615-2627 ◽

Cited By ~ 2

Author(s):

Xiaodong Zhu ◽

Gregory Mahairas ◽

Michele Illies ◽

R. Andrew Cameron ◽

Eric H. Davidson ◽

...

Keyword(s):

Sea Urchin ◽

Large Scale ◽

Surface Proteins ◽

Matrix Proteins ◽

Specific Cell ◽

Gastrula Stage ◽

Sea Urchin Embryo ◽

Expressed Sequenced Tags ◽

Mesenchyme Cells ◽

Primary Mesenchyme Cells

The primary mesenchyme cells (PMCs) of the sea urchin embryo have been an important model system for the analysis of cell behavior during gastrulation. To gain an improved understanding of the molecular basis of PMC behavior, a set of 8293 expressed sequenced tags (ESTs) was derived from an enriched population of mid-gastrula stage PMCs. These ESTs represented approximately 1200 distinct proteins, or about 15% of the mRNAs expressed by the gastrula stage embryo. 655 proteins were similar (P<10−7 by BLAST comparisons) to other proteins in GenBank, for which some information is available concerning expression and/or function. Another 116 were similar to ESTs identified in other organisms, but not further characterized. We conservatively estimate that sequences encoding at least 435 additional proteins were included in the pool of ESTs that did not yield matches by BLAST analysis. The collection of newly identified proteins includes many candidate regulators of primary mesenchyme morphogenesis, including PMC-specific extracellular matrix proteins, cell surface proteins, spicule matrix proteins and transcription factors. This work provides a basis for linking specific molecular changes to specific cell behaviors during gastrulation. Our analysis has also led to the cloning of several key components of signaling pathways that play crucial roles in early sea urchin development.

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Faculty Opinions recommendation of Specific functions of the Wnt signaling system in gene regulatory networks throughout the early sea urchin embryo.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725231801.793514586 ◽

2016 ◽

Author(s):

David McClay

Keyword(s):

Wnt Signaling ◽

Sea Urchin ◽

Gene Regulatory Networks ◽

Regulatory Networks ◽

Signaling System ◽

Sea Urchin Embryo ◽

Gene Regulatory

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Involvement of Huntingtin in Development and Ciliary Beating Regulation of Larvae of the Sea Urchin, Hemicentrotus pulcherrimus

International Journal of Molecular Sciences ◽

10.3390/ijms22105116 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5116

Author(s):

Hideki Katow ◽

Tomoko Katow ◽

Hiromi Yoshida ◽

Masato Kiyomoto

Keyword(s):

Sea Urchin ◽

The Body ◽

Brdu Incorporation ◽

Wild Type ◽

Blastula Stage ◽

Ciliary Beating ◽

Marker Proteins ◽

Disease Protein ◽

Pattern Regulation ◽

Hemicentrotus Pulcherrimus

The multiple functions of the wild type Huntington’s disease protein of the sea urchin Hemicentrotus pulcherrimus (Hp-Htt) have been examined using the anti-Hp-Htt antibody (Ab) raised against synthetic oligopeptides. According to immunoblotting, Hp-Htt was detected as a single band at around the 350 kDa region at the swimming blastula stage to the prism larva stage. From the 2-arm pluteus stage (2aPL), however, an additional smaller band at the 165 kDa region appeared. Immunohistochemically, Hp-Htt was detected in the nuclei and the nearby cytoplasm of the ectodermal cells from the swimming blastula stage, and the blastocoelar cells from the mid-gastrula stage. The Ab-positive signal was converged to the ciliary band-associated strand (CBAS). There, it was accompanied by several CBAS-marker proteins in the cytoplasm, such as glutamate decarboxylase. Application of Hp-Htt morpholino (Hp-Htt-MO) has resulted in shortened larval arms, accompanied by decreased 5-bromo-2-deoxyuridin (BrdU) incorporation by the ectodermal cells of the larval arms. Hp-Htt-MO also resulted in lowered ciliary beating activity, accompanied by a disordered swirling pattern formation around the body. These Hp-Htt-MO-induced deficiencies took place after the onset of CBAS system formation at the larval arms. Thus, Hp-Htt is involved in cell proliferation and the ciliary beating pattern regulation signaling system in pluteus larvae.

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Localization and expression of msp130, a primary mesenchyme lineage-specific cell surface protein in the sea urchin embryo

Development ◽

10.1242/dev.101.2.255 ◽

1987 ◽

Vol 101 (2) ◽

pp. 255-265 ◽

Cited By ~ 4

Author(s):

J.A. Anstrom ◽

J.E. Chin ◽

D.S. Leaf ◽

A.L. Parks ◽

R.A. Raff

Keyword(s):

Cell Surface ◽

Sea Urchin ◽

Sea Water ◽

Surface Protein ◽

Specific Cell ◽

Cell Surface Protein ◽

Sea Urchin Embryo ◽

A Cell ◽

Mesenchyme Cells ◽

Primary Mesenchyme Cells

In this report, we use a monoclonal antibody (B2C2) and antibodies against a fusion protein (Leaf et al. 1987) to characterize msp130, a cell surface protein specific to the primary mesenchyme cells of the sea urchin embryo. This protein first appears on the surface of these cells upon ingression into the blastocoel. Immunoelectronmicroscopy shows that msp130 is present in the trans side of the Golgi apparatus and on the extracellular surface of primary mesenchyme cells. Four precursor proteins to msp130 are identified and we show that B2C2 recognizes only the mature form of msp130. We demonstrate that msp130 contains N-linked carbohydrate groups and that the B2C2 epitope is sensitive to endoglycosidase F digestion. Evidence that msp130 is apparently a sulphated glycoprotein is presented. The recognition of the B2C2 epitope of msp130 is disrupted when embryos are cultured in sulphate-free sea water. In addition, two-dimensional immunoblots show that msp130 is an acidic protein that becomes substantially less acidic in the absence of sulphate. We also show that two other independently derived monoclonal antibodies, IG8 (McClay et al. 1983; McClay, Matranga & Wessel, 1985) and 1223 (Carson et al. 1985), recognize msp130, and suggest this protein to be a major cell surface antigen of primary mesenchyme cells.

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Primary mesenchyme cells of the sea urchin embryo require an autonomously produced, nonfibrillar collagen for spiculogenesis

Developmental Biology ◽

10.1016/0012-1606(91)90335-z ◽

1991 ◽

Vol 148 (1) ◽

pp. 261-272 ◽

Cited By ~ 34

Author(s):

Gary M. Wessel ◽

Marc Etkin ◽

Steve Benson

Keyword(s):

Sea Urchin ◽

Sea Urchin Embryo ◽

Mesenchyme Cells ◽

Primary Mesenchyme Cells

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Cell interactions and mesodermal cell fates in the sea urchin embryo

Development ◽

10.1242/dev.116.supplement.43 ◽

1992 ◽

Vol 116 (Supplement) ◽

pp. 43-51 ◽

Cited By ~ 7

Author(s):

Charles A. Ettensohn

Keyword(s):

Sea Urchin ◽

Cell Interactions ◽

Cell Labeling ◽

Cell Fates ◽

Mesodermal Cell ◽

Sea Urchin Embryo ◽

Present Information ◽

Cell Type Specific ◽

Mesenchyme Cells

Cell interactions during gastrulation play a key role in the determination of mesodermal cell fates in the sea urchin embryo. An interaction between primary and secondary mesenchyme cells (PMCs and SMCs, respectively), the two principal populations of mesodermal cells, regulates the expression of SMC fates. PMCs are committed early in cleavage to express a skeletogenic phenotype. During gastrulation, they transmit a signal that suppresses the skeletogenic potential of a subpopulation of SMCs and directs these cells into an alternative developmental pathway. This review summarizes present information concerning the cellular basis of the PMC-SMC interaction, as analyzed by cell transplantation and ablation experiments, fluorescent cell labeling methods and the use of cell type-specific molecular markers. The nature and stability of SMC fate switching, the timing of the PMC-SMC interaction and its quantitative characteristics, and the lineage, numbers and normal fate of the population of skeletogenic SMCs are discussed. Evidence is presented indicating that PMCs and SMCs come into direct filopodial contact during the late gastrula stage, when the signal is transmitted. Finally, evolutionary questions raised by these studies are briefly addressed.

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The role of secondary mesenchyme cells during sea urchin gastrulation studied by laser ablation

Development ◽

10.1242/dev.103.2.317 ◽

1988 ◽

Vol 103 (2) ◽

pp. 317-324 ◽

Cited By ~ 1

Author(s):

J. Hardin

Keyword(s):

Laser Ablation ◽

Sea Urchin ◽

Normal Rate ◽

Common Mechanism ◽

Gastrula Stage ◽

Mechanical Tension ◽

Lytechinus Pictus ◽

Final Length ◽

Mesenchyme Cells

It has long been thought that traction exerted by filopodia of secondary mesenchyme cells (SMCs) is a sufficient mechanism to account for elongation of the archenteron during sea urchin gastrulation. The filopodial traction hypothesis has been directly tested here by laser ablation of SMCs in gastrulae of the sea urchin, Lytechinus pictus. When SMCs are ablated at the onset of secondary invagination, the archenteron doubles in length at the normal rate of elongation, but advance of the tip of the archenteron stops at the 2/3 gastrula stage. In contrast, when all SMCs are ablated at or following the 2/3 gastrula stage, further elongation does not occur. However, if a few SMCs are allowed to remain in 2/3-3/4 gastrulae, elongation continues, although more slowly than in controls. The final length of archenterons in embryos ablated at the 1/3-1/2 gastrula stage is virtually identical to the final length of everted archenterons in LiCl-induced exogastrulae; since filopodial traction is not exerted in either case, an alternate, common mechanism of elongation probably operates in both cases. These results suggest that archenteron elongation involves two processes: (1) active, filopodia-independent elongation, which depends on active cell rearrangement and (2) filopodia-dependent elongation, which depends on mechanical tension exerted by the filopodia.

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