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A Manual Small Molecule Screen Approaching High-throughput Using Zebrafish Embryos
Published on: November 8, 2014
Retinoic acid receptor subtype-specific transcriptotypes in the early zebrafish embryo
Eric Samarut1, Cyril Gaudin, Sandrine Hughes
1Institut de Génomique Fonctionnelle de Lyon (E.S., C.G., S.H., B.G., L.B., V.L.), Université de Lyon, Université Lyon 1, Centre National de la Recherche Scientifique (CNRS), Ecole Normale Supérieure de Lyon, 69364 Lyon Cedex 07, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire (E.S., A.A., O.L., C.R.-E.), Institut National de la Sante et de la Recherche Medicale, U596, CNRS, UMR7104, Université de Strasbourg, BP 10142, 67404 Illkirch Cedex, France.; and AltraBio SAS (S.B., P.-E.J., L.B.), Lyon, France.
Retinoic acid receptors (RARs) have distinct roles in embryonic development, not just redundant ones. This study defines RAR subtype-specific transcriptotypes, revealing unique gene activation patterns for each receptor.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Retinoic acid (RA) signaling is crucial for embryonic development, mediated by retinoic acid receptors (RARs).
- Vertebrates possess three RAR subtypes with known common and specific roles, but subtype-specific functions in co-expressing regions remain unclear.
Purpose of the Study:
- To investigate whether RAR subtypes exhibit distinct transcriptional activities in vivo.
- To identify subtype-specific gene expression patterns (transcriptotypes) regulated by RA signaling.
Main Methods:
- Utilized zebrafish embryos as a model system for studying early embryonic development.
- Employed morpholino knockdown to specifically invalidate endogenous RAR subtypes in vivo.
- Conducted whole-transcriptome analysis to identify RA-responsive genes and compare them across different RAR knockdown conditions.
Main Results:
- RAR subtypes do not possess fully redundant functions; they transduce RA signals in a subtype-specific manner.
- Defined RAR subtype-specific transcriptotypes, representing unique repertoires of genes activated by different RARs.
- Identified RA pathway genes (e.g., cyp26a1, raraa) with robust regulation, maintaining signaling integrity even when all RARs are knocked down.
Conclusions:
- RAR subtypes mediate distinct transcriptional outputs, challenging the notion of complete functional redundancy.
- The concept of RAR subtype-specific transcriptotypes provides a new framework for understanding RA signaling complexity.
- Certain RA-responsive genes exhibit high robustness, ensuring pathway integrity despite alterations in RAR expression.
