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Updated: Aug 5, 2025
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Embryo Microinjection and Electroporation in the Chordate Ciona intestinalis
Published on: October 16, 2016
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Zic-r.b controls cell numbers in Ciona embryos by activating CDKN1B
Nicholas Treen1, Shohei Konishi2, Hiroki Nishida2
1Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka, 415-0025, Japan.
Developmental Biology
|March 25, 2023
Summary
The transcription factor Zic-r.b controls cell numbers and types during embryonic development by activating cell cycle inhibitors. Its earlier expression in larvaceans explains their reduced notochord cell count, revealing a mechanism for morphological evolution.
Area of Science:
- Developmental biology
- Evolutionary biology
- Cell cycle regulation
Background:
- Cell number control and cell type specification are crucial for embryonic development.
- The interplay between these processes is not well understood.
- Tunicates, with fixed cell lineages, are ideal models for studying these developmental mechanisms.
Purpose of the Study:
- To investigate the role of the transcription factor Zic-r.b in linking cell number and cell type determination in ascidian embryos.
- To compare the expression patterns of Zic-r.b homologs in ascidians and larvaceans to understand evolutionary changes in cell lineages.
Main Methods:
- Utilized the ascidian Ciona as a model organism.
- Investigated the function of the transcription factor Zic-r.b.
- Analyzed the expression of the cell cycle inhibitor CDKN1B.
- Compared Zic-r.b homolog expression between ascidians and larvaceans.
Main Results:
- Zic-r.b activates the expression of the cell cycle inhibitor CDKN1B in Ciona.
- Zic-r.b is identified as a key regulator of the cell division clock, influencing specific cell numbers.
- A larvacean Zic-r.b homolog is expressed one cell cycle earlier than in Ciona.
Conclusions:
- Zic-r.b integrates cell type specification with cell cycle control during embryonic development.
- The timing of Zic-r.b expression is a critical factor in determining notochord cell numbers in tunicates.
- Evolutionary shifts in Zic-r.b expression timing may drive morphological diversification.
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