ABSTRACT
I was recruited by François Gros as a PhD student in his laboratory at the Institut de Biologie Physico-Chimique in 1965, and continued to work with him after I graduated. In 1973, when he was appointed Professor of Cellular Biochemistry at the Collège de France, François decided to set up a team working on neuronal differentiation. He asked me to take part in this new scientific adventure. Here I'd like to talk about the members of his laboratory and some of their scientific work, in particular that on the cytoskeleton of neurons.
J'ai été recrutée par François Gros comme étudiante dans son laboratoire à l'Institut de Biologie Physico-Chimique en 1965 et j'ai continué à travailler avec lui après ma thèse. En 1973, quand il a été nommé professeur titulaire de la chaire de Biochimie cellulaire au Collège de France, François a décidé d'y créer une équipe travaillant sur la différenciation des cellules nerveuses. Il m'a demandé de participer à cette nouvelle aventure scientifique. J'évoque ici les membres de son laboratoire ainsi que certains de leurs travaux scientifiques, notamment ceux concernant le cytosquelette des neurones.
Subject(s)
Microtubules , Neurons , Humans , Male , FranceABSTRACT
The glucocorticoid receptor is a ubiquitous transcription factor mediating adaptation to environmental challenges and stress. Selective Nr3c1 (the glucocorticoid receptor gene) ablation in mouse dopaminoceptive neurons expressing dopamine receptor 1a, but not in dopamine-releasing neurons, markedly decreased the motivation of mice to self-administer cocaine, dopamine cell firing and the control exerted by dopaminoceptive neurons on dopamine cell firing activity. In contrast, anxiety was unaffected, indicating that glucocorticoid receptors modify a number of behavioral disorders through different neuronal populations.
Subject(s)
Behavior, Addictive/metabolism , Cocaine/administration & dosage , Dopamine/physiology , Neurons/physiology , Receptors, Glucocorticoid/physiology , Stress, Psychological/metabolism , Animals , Behavior, Addictive/genetics , Behavior, Addictive/psychology , Cocaine/antagonists & inhibitors , Cocaine-Related Disorders/genetics , Cocaine-Related Disorders/metabolism , Cocaine-Related Disorders/psychology , Dopamine/metabolism , Mice , Mice, Transgenic , Neurons/metabolism , Receptors, Dopamine D1/antagonists & inhibitors , Receptors, Dopamine D1/metabolism , Receptors, Glucocorticoid/antagonists & inhibitors , Receptors, Glucocorticoid/biosynthesis , Receptors, Glucocorticoid/genetics , Self Administration , Stress, Psychological/genetics , Stress, Psychological/psychologyABSTRACT
The 5-HT1A receptor not only plays an important role in brain physiology but it may be also implicated in the etiology of behavioral disorders such as pathological anxiety. To further define the role of 5-HT1A receptor-expressing neurons, we generated a transgenic mouse line expressing Cre recombinase in these cells. The 5-HT1A receptor open reading frame was substituted for that of Cre recombinase in a BAC containing the 5-HT1A receptor gene. In adult transgenic brain, Cre expression perfectly matched the distribution of 5-HT1A receptor mRNA. Additionally, Cre-mediated DNA recombination was restricted to neuronal populations that express the receptor, e.g., cerebral cortex, septum, hippocampus, dorsal raphe, thalamic, hypothalamic and amygdaloid nuclei, and spinal cord. Recombination occurred as early as E13 in trigeminal nerve, spinal ganglia and spinal cord. This transgenic line will allow the generation of conditional mutant mice that lack specific gene products along the serotonergic pathways and represents a unique tool for studying 5-HT1A-mediated serotonin signaling in the developing and adult brain.
Subject(s)
Brain/metabolism , Integrases/metabolism , Mice, Transgenic/genetics , Receptor, Serotonin, 5-HT1A/genetics , Serotonin/metabolism , Signal Transduction/genetics , Animals , Behavior, Animal/physiology , Brain/embryology , Brain/growth & development , Embryo, Mammalian , Gene Expression Regulation, Developmental/genetics , Integrases/genetics , Mice , Mice, Inbred C57BL , Serotonin/geneticsABSTRACT
The dopamine transporter is an essential component of the dopaminergic synapse. It is located in the presynaptic neurons and regulates extracellular dopamine levels. We generated a transgenic mouse line expressing the Cre recombinase under the control of the regulatory elements of the dopamine transporter gene, for investigations of gene function in dopaminergic neurons. The codon-improved Cre recombinase (iCre) gene was inserted into the dopamine transporter gene on a bacterial artificial chromosome. The pattern of expression of the bacterial artificial chromosome-dopamine transporter-iCre transgene was similar to that of the endogenous dopamine transporter gene, as shown by immunohistochemistry. Recombinase activity was further studied in mice carrying both the bacterial artificial chromosome-dopamine transporter-iCre transgene and a construct expressing the beta-galactosidase gene after Cre-mediated recombination. In situ studies showed that beta-galactosidase (5-bromo-4-chloroindol-3-yl beta-D-galactoside staining) and the dopamine transporter (immunofluorescence) had identical distributions in the ventral midbrain. We used this animal model to study the distribution of dopamine transporter gene expression in hypothalamic nuclei in detail. The expression profile of tyrosine hydroxylase (an enzyme required for dopamine synthesis) was broader than that of beta-galactosidase in A12 to A15. Thus, only a fraction of neurons synthesizing dopamine expressed the dopamine transporter gene. The bacterial artificial chromosome-dopamine transporter-iCre transgenic line is a unique tool for targeting Cre/loxP-mediated DNA recombination to dopamine neurons for studies of gene function or for labeling living cells, following the crossing of these mice with transgenic Cre reporter lines producing fluorescent proteins.
Subject(s)
Dopamine Plasma Membrane Transport Proteins/genetics , Gene Expression Profiling , Gene Expression Regulation/genetics , Integrases/metabolism , Animals , Behavior, Animal , Dopamine Plasma Membrane Transport Proteins/analysis , Dopamine Plasma Membrane Transport Proteins/metabolism , Integrases/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Motor Activity , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , beta-Galactosidase/metabolismABSTRACT
The cDNA for rabbit muscle-specific (betabeta) enolase was cloned, sequenced and expressed in Escherichia coli. This betabeta-enolase differs at eight positions from that sequenced by Chin (17). Site-directed mutagenesis was used to change residue 414 from glutamate to leucine, thereby abolishing a salt bridge involved in subunit contacts. Recombinant wild-type and mutant enolase were purified from E. coli and compared to enolase isolated from rabbit muscle. Molecular weights were determined by mass spectrometry. All three betabeta-enolases had similar kinetics, and UV and circular dichroism (CD) spectra. The mutant enolase was far more sensitive to inactivation by pressure, by KCl or EDTA, and by sodium perchlorate. We confirmed, by analytical ultracentrifugation, that the sodium perchlorate inactivation was due to dissociation. DeltaG(o) for dissociation of enolase was decreased from 49.7 kJ/mol for the wild-type enzyme to 42.3 kJ/mol for the mutant. In contrast to the wild-type enzyme, perchlorate inactivation of E414L was accompanied by a small loss of secondary structure.
