Centre National de la Recherche Scientifique (CNRS) France

Leader: Patrick Lemaire

Brief description of the organisation:
The Institut de Biologie du Developpement de Marseille-Luminy is the main centre for developmental biology in Southern France and a leader in the country as a whole. It hosts 23 research groups exploring the development of a variety of model organisms ranging from Drosophila to Man, with special emphasis on neural development. The institute actively encourages the use of multidisciplinary approaches to address developmental issues.

Main tasks attributed to the project:
The main contribution of this partner is to analyse the Ciona gene networks underlying dopaminergic neuron formation. For this, dopaminergic neurones will first be made fluorescent by transgenesis and purified. Large-scale transcriptome analysis will point to important regulatory genes, whose function will be analysed by gain and loss of function. An analysis of the conservation of the regulatory logic between Ciona and vertebrates will ensue.

Previous experience relevant to the tasks:
Lemaire's lab has largely contributed to deciphering gene regulatory networks specifying the Ciona nervous system. The group identified major early determinants of the ectodermal/mesendodermal and antero/posterior axes, as well as some of their direct target genes (Lamy, Rothbacher et al. 2006).
Downstream of the specification of the ectoderm, they showed that FGF9/16/20 is the major inducer of anterior neural tissues and dissected the cis-regulatory logic restricting the response to widely expressed FGF to specific neural precursors (Bertrand, Hudson et al. 2003; Tassy, Daian et al. 2006). They also analysed the formation of the peripheral epidermal sensory neurons (Pasini, Amiel et al. 2006). The group is now applying larger throughput and bioinformatics analyses to extend these networks and identify the cis-regulatory regions of most network nodes of the networks.
The Lemaire lab developed the following molecular and bioinformatics tools:
  1. A suite of Gateway-based expression vectors used across chordates
  2. A full ORF Unigene set, compatible with the Chordate Gateway expression vector suite and allowing efficient gain of function analyses
  3. A collection of ~70 cis-regulatory modules for neural regulatory genes.
  4. A major database for ascidians, ANISEED, (Tassy, Daian et al. 2006)
  5. A suite of tools aimed at data integration in regulatory networks discovery

Selected recent publications:

  • Rothbächer U., Bertrand V., Lamy C., and Lemaire P. (2007) A Combinatorial Code Of Maternal GATA, Ets And ß-Catenin/Tcf Transcription Factors Specifies And Patterns The Early Ascidian Ectoderm. Development in press.
  • Roure A., Rothbächer U., Robin F., Kalmar E., Lamy C., Missero C., Müller F. and Lemaire P. (2007) A Multicassette Gateway Vector Set For High Throughput And Comparative Analyses In Ciona And Vertebrate Embryos. PLoS-ONE in press.
  • Lamy C., Rothbächer U., Caillol D. and Lemaire P. (2006) Ci-Foxaa Is The Earliest Zygotic Determinant Of The Ascidian Anterior Ectoderm And Directly Activates Ci-SFRP1/5 Development 133:2835-44.
  • Pasini A., Amiel A., Rothbächer U., Roure A., Lemaire P., and Darras S. (2006) A Two Step Model For The Formation Of The Ascidian Epidermal Sensory Neurons: Insights Into The Origin Of Chordate Peripheral Nervous System. PLoS Biology 4(7):e225
  • Lemaire P. (2006) How Many Ways To Make A Chordate? Science 312:1145-1146