Abstract
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 of beta-catenin, suggesting that HpTb is in a downstream component of the Wnt signaling cascade. We also propose the possibility that HpTb is 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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Arsenite Transporting ATPases
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Base Sequence
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Blastula / cytology
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Blastula / metabolism
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Cell Nucleus / metabolism
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / metabolism
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Ectoderm
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Embryo, Nonmammalian
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Embryonic Induction
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Gastrula
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Gene Expression Regulation, Developmental
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Ion Pumps / genetics
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Ion Pumps / metabolism
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Mice
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Molecular Sequence Data
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Multienzyme Complexes / genetics
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Multienzyme Complexes / metabolism
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Protein Biosynthesis
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Sea Urchins / embryology*
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Sea Urchins / genetics
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Sequence Homology, Amino Acid
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Signal Transduction
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T-Box Domain Proteins / genetics*
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T-Box Domain Proteins / metabolism*
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Trans-Activators / genetics
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Trans-Activators / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism
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beta Catenin
Substances
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CTNNB1 protein, mouse
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Cytoskeletal Proteins
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HpEts protein, Hemicentrotus pulcherrimus
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Ion Pumps
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Multienzyme Complexes
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T-Box Domain Proteins
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Trans-Activators
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Transcription Factors
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beta Catenin
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SM30 protein, Strongylocentrotus purpuratus
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Arsenite Transporting ATPases
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Asna1 protein, mouse