Abstract: The invention relates to a method for optical detection of the dynamics of Ca2+ in a biological system, said method comprising monitoring the photons emitted by a recombinant Ca2+-sensitive polypeptide, which comprises or consists of a chemiluminescent protein linked to a fluorescent protein, present in said biological system. In a particular embodiment, said recombinant polypeptide comprises or consists of the Aequorin and GFP linked by a linker allowing chemiluminescence resonance energy transfer (CRET), and optionally comprises a peptidic fragment capable of targeting said recombinant polypeptide into a specific cellular domain or compartment. The present invention also concerns a transgenic non-human animal expressing said recombinant polypeptide sensitive to calcium concentration, in conditions enabling the in vivo monitoring of Ca2+ dynamics.

Abstract: A method for visualizing an active synapse wherein said method comprises: (a) exposing cells forming the active synapse to a biomarker comprising at least fragment C of tetanus toxin and a reporter protein; and (b) visualizing the biomarker; wherein the accumulation of the biomarker into dendritic spines of the cells allows visualization of an active synapse. Also, a method for screening molecules capable of modulating synapse activity is provided. A kit useful for the early diagnosis of neurodegenerative disease comprises a biomarker comprising at least fragment C of tetanus toxin and a reporter protein.

Abstract: A hybrid protein (GFP-TTC) comprising the non-toxic proteolytic C fragment of tetanus toxin fused to green fluorescent protein was used to analyze the functional synaptic organization of neural networks. When injected intramuscularly in vivo, the GFP-TTC hybrid protein binds to tetanus neurotoxin receptors and clusters very rapidly to the active neuromuscular junction. Membrane traffic by GFP-TTC at the pre-synaptic level of the neuromuscular junction is strongly and rapidly influenced by exogenously co-injecting neurotrophic factors, such as BDNF, NT-4, and GDNF, but not by NGF, NT-3, and CNTF. The membrane traffic, directly detected using GFP-TTC in vivo, permits methods of analyzing synaptic functioning as well as methods of modulating neuronal transport using neurotrophic factors and agonists or antagonists thereof.

Abstract: The non-toxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. A hybrid protein encoded by the LacZ-TTC gene fusion retains the biological functions of both proteins in vivo, i.e. retrograde transynaptic transport of the TTC fragment and ?gal enzymatic activity. After intramuscular injection, enzymatic activity can be detected in motoneurons and connected neurons of brainstem areas. This strategy is useful for the delivery of a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein can also be used to map synaptic connections between neural cells.

Abstract: A modified bioluminescent system comprising a fluorescent molecule covalently linked with a photoprotein, wherein said link between the two proteins has the function to stabilize the modified bioluminescent system and allowing the transfer of the energy by Chemiluminescence Resonance Energy Transfer (CRET).

Abstract: The invention relates to means for in vivo delivery of a composition into the human or animal central nervous system or spinal cord, wherein the composition comprises a non-toxic, proteolytic fragment of tetanus toxoid in association with at least a molecule having a biological function, and said molecule is capable of in vivo retrograde axonal transport and transynaptic transport into the CNS or spinal cord of the human or animal. In a particular embodiment, the composition comprises a fragment C and a fragment B of tetanus toxoid or a fraction thereof of at least 11 amino acid residues. The composition can further comprise a fraction of fragment A of tetanus toxoid.

Abstract: The non-toxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. A hybrid protein encoded by the IacZ-TTC gene fusion retains the biological functions of both proteins in vivo, i.e. retrograde transynaptic transport of the TTC fragment and ?-gal enzymatic activity. After intramuscular injection, enzymatic activity could be detected in motoneurons and connected neurons of the brainstem areas. This strategy is useful for the delivery of a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein can also be used to map synaptic connections between neural cells.

Abstract: A modified bioluminescent system comprising a fluorescent molecule covalently linked with a photoprotein, wherein said link between the two proteins has the function to stabilize the modified bioluminescent system and allowing the transfer of the energy by Chemiluminescence Resonance Energy Transfer(CRET).

Abstract: A method for visualizing an active synapse wherein said method comprises: (a) exposing cells forming the active synapse to a biomarker comprising at least fragment C of tetanus toxin and a reporter protein; and (b) visualizing the biomarker; wherein the accumulation of the biomarker into dendritic spines of the cells allows visualization of an active synapse. Also, a method for screening molecules capable of modulating synapse activity is provided. A kit useful for the early diagnosis of neurodegenerative disease comprises a biomarker comprising at least fragment C of tetanus toxin and a reporter protein.

Abstract: The non-toxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. A hybrid protein encoded by the lacZ-TTC gene fusion retains the biological functions of both proteins in vivo, i.e. retrograde transynaptic transport of the TTC fragment and -gal enzymatic activity. After intramuscular injection, enzymatic activity could be detected in motoneurons and connected neurons of the brainstem areas. This strategy is useful for the delivery of a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein can also be used to map synaptic connections between neural cells.

Abstract: A method for bioluminescence imaging in an animal is provided. The method comprises providing a whole animal containing a transcriptionally active nucleic acid sequence encoding a Ca2+-sensitive polypeptide, which comprises a chemiluminescent protein linked to a fluorescent protein; and monitoring photons emitted by the Ca2+-sensitive polypeptide. The Ca2+-sensitive polypeptide comprises aequorin protein covalently linked to a YFP (yellow fluorescent protein) or RFP (red fluorescent protein), and the link between the two proteins functions to allow luminescence by energy transfer between the two proteins. The photons are monitored from deep tissues of the animal.

Abstract: The non-toxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. A hybrid protein encoded by the IacZ-TTC gene fusion retains the biological functions of both proteins in vivo, i.e. retrograde transynaptic transport of the TTC fragment and ?-gal enzymatic activity. After intramuscular injection, enzymatic activity could be detected in motoneurons and connected neurons of the brainstem areas. This strategy is useful for the delivery of a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein can also be used to map synaptic connections between neural cells.

Abstract: A modified bioluminescent system comprising a fluorescent molecule covalently linked with a photoprotein, wherein said link between the two proteins has the function to stabilize the modified bioluminescent system and allowing the transfer of the energy by Chemiluminescence Resonance Energy Transfer(CRET).

Abstract: DNA gene inactivation constructs for homologous recombination in the genome of a mammalian cell are provided.

Abstract: The invention relates to a method for optical detection of the dynamics of Ca2+ in a biological system, said method comprising monitoring the photons emitted by a recombinant Ca2+-sensitive polypeptide, which comprises or consists of a chemiluminescent protein linked to a fluorescent protein, present in said biological system. In a particular embodiment, said recombinant polypeptide comprises or consists of the Aequorin and GFP linked by a linker allowing chemiluminescence resonance energy transfer (CRET), and optionally comprises a peptidic fragment capable of targeting said recombinant polypeptide into a specific cellular domain or compartment. The present invention also concerns a transgenic non-human animal expressing said recombinant polypeptide sensitive to calcium concentration, in conditions enabling the in vivo monitoring of Ca2+ dynamics.

Abstract: A method for visualizing an active synapse wherein said method comprises: (a) exposing cells forming the active synapse to a biomarker comprising at least fragment C of tetanus toxin and a reporter protein; and (b) visualizing the biomarker; wherein the accumulation of the biomarker into dendritic spines of the cells allows visualization of an active synapse. Also, a method for screening molecules capable of modulating synapse activity is provided. A kit useful for the early diagnosis of neurodegenerative disease comprises a biomarker comprising at least fragment C of tetanus toxin and a reporter protein.

Abstract: The invention relates to means for in vivo delivery of a composition into the human or animal central nervous system or spinal cord, wherein the composition comprises a non-toxic, proteolytic fragment of tetanus toxoid in association with at least a molecule having a biological function, and said molecule is capable of in vivo retrograde axonal transport and transynaptic transport into the CNS or spinal cord of the human or animal. In a particular embodiment, the composition comprises a fragment C and a fragment B of tetanus toxoid or a fraction thereof of at least 11 amino acid residues. The composition can further comprise a fraction of fragment A of tetanus toxoid.

Abstract: The invention relates to a method for optical detection of the dynamics of Ca2+ in a biological system, said method comprising monitoring the photons emitted by a recombinant Ca2+-sensitive polypeptide, which comprises or consists of a chemiluminescent protein linked to a fluorescent protein, present in said biological system. In a particular embodiment, said recombinant polypeptide comprises or consists of the Aequorin and GFP linked by a linker allowing chemiluminescence resonance energy transfer (CRET), and optionally comprises a peptidic fragment capable of targeting said recombinant polypeptide into a specific cellular domain or compartment. The present invention also concerns a transgenic non-human animal expressing said recombinant polypeptide sensitive to calcium concentration, in conditions enabling the in vivo monitoring of Ca2+ dynamics.

Abstract: A modified bioluminescent system comprising a fluorescent molecule covalently linked with a photoprotein, wherein said link between the two proteins has the function to stabilize the modified bioluminescent system and allowing the transfer of the energy by Chemiluminescence Resonance Energy Transfer (CRET).

Abstract: A method for visualizing an active synapse wherein said method comprises: (a) exposing cells forming the active synapse to a biomarker comprising at least fragment C of tetanus toxin and a reporter protein; and (b) visualizing the biomarker; wherein the accumulation of the biomarker into dendritic spines of the cells allows visualization of an active synapse. Also, a method for screening molecules capable of modulating synapse activity is provided. A kit useful for the early diagnosis of neurodegenerative disease comprises a biomarker comprising at least fragment C of tetanus toxin and a reporter protein.