PUBLICATION
Cooperation of sonic hedgehog enhancers in midline expression
- Authors
- Ertzer, R., Muller, F., Hadzhiev, Y., Rathnam, S., Fischer, N., Rastegar, S., and Strähle, U.
- ID
- ZDB-PUB-061227-30
- Date
- 2007
- Source
- Developmental Biology 301(2): 578-589 (Journal)
- Registered Authors
- Ertzer, Raymond, Fischer, Nadine, Hadzhiev, Yavor, Müller, Ferenc, Rastegar, Sepand, Rathnam, Saradavey, Strähle, Uwe
- Keywords
- Embryonic shield, Notochord, Floor plate, Zona limitans intrathalamica, Hypothalamus, Zebrafish, Sonic hedgehog, Transgene, Enhancer
- MeSH Terms
-
- Animals
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- Enhancer Elements, Genetic
- Gene Expression*
- Gene Expression Regulation, Developmental
- Genes, Reporter/genetics
- Hedgehog Proteins/genetics
- Hedgehog Proteins/metabolism*
- Hypothalamus/embryology
- Hypothalamus/metabolism
- Notochord/embryology
- Notochord/metabolism
- Prosencephalon/embryology
- Prosencephalon/metabolism
- Somites/metabolism
- Time Factors
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/metabolism
- PubMed
- 17157288 Full text @ Dev. Biol.
Citation
Ertzer, R., Muller, F., Hadzhiev, Y., Rathnam, S., Fischer, N., Rastegar, S., and Strähle, U. (2007) Cooperation of sonic hedgehog enhancers in midline expression. Developmental Biology. 301(2):578-589.
Abstract
In zebrafish, as in other vertebrates, the secreted signalling molecule Sonic hedgehog (Shh) is expressed in organiser regions such as the embryonic midline and the zona limitans intrathalamica (zli). To investigate the regulatory mechanisms underlying the pattern of shh expression, we carried out a systematic analysis of the intronic regulatory sequences of zebrafish shh using stable transgenesis. Deletion analysis identified the modules responsible for expression in the embryonic shield, the hypothalamus and the zli and confirmed the activities of previously identified notochord and floor plate enhancers. We detected a strong synergism between regulatory regions. The degree of synergy varied over time in the hypothalamus suggesting different mechanisms for initiation and maintenance of expression. Our data show that the pattern of shh expression in the embryonic central nervous system involves an intricate crosstalk of at least 4 different regulatory regions. When compared to the enhancer activities of the mouse Shh gene, we observed a remarkable divergence of function of structurally conserved enhancer sequences. The activating region ar-C (61% identical to SFPE2 in mouse Shh), for example, mediates floor plate expression in the mouse embryo while it directs expression in the forebrain and the notochord and only weakly in the floor plate in the zebrafish embryo. This raises doubts on the predictive power of phylogenetic footprinting and indicates a stunning divergence of function of structurally conserved regulatory modules during vertebrate evolution.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping