Analytical model of internally coupled ears.

Lizards and many birds possess a specialized hearing mechanism: internally coupled ears where the tympanic membranes connect through a large mouth cavity so that the vibrations of the tympanic membranes influence each other. This coupling enhances the phase differences and creates amplitude differences in the tympanic membrane vibrations. Both cues show strong directionality.

Optimality in mono- and multisensory map formation.

In the struggle for survival in a complex and dynamic environment, nature has developed a multitude of sophisticated sensory systems. In order to exploit the information provided by these sensory systems, higher vertebrates reconstruct the spatio-temporal environment from each of the sensory systems they have at their disposal. That is, for each modality the animal computes a neuronal representation of the outside world, a monosensory neuronal map.

Identification of the 'NORE' (N-Oct-3 responsive element), a novel structural motif and composite element.

N-Oct-3 is a neuronal transcription factor widely expressed in the developing mammalian central nervous system, and necessary to maintain neural cell differentiation. The key role of N-Oct-3 in the transcriptional regulation of a multiplicity of genes is primarily due to the structural plasticity of its so-called 'POU' (acronym of Pit, Oct, Unc) DNA-binding domain. We have recently reported about the unusual dual neuro-specific transcriptional regulation displayed by N-Oct-3 [Blaud,M.

Effect of electric field vectoriality on electrically mediated gene delivery in mammalian cells.

Electropermeabilization is a nonviral method used to transfer genes into living cells. Up to now, the mechanism is still to be elucidated. Since cell permeabilization, a prerequired for gene transfection, is triggerred by electric field, its characteristics should depend on its vectorial properties.

Characteristic patterns of N Oct-3 binding to a set of neuronal promoters.

N Oct-3, a neurospecific POU protein, homodimerizes in a non-cooperative fashion on the neuronal aromatic l-amino acid decarboxylase gene promoter and generates heterodimers with HNF-3beta. Several other neuronal gene promoters, the corticotropin releasing hormone and the aldolase C gene promoters also contain overlapping binding sites for N Oct-3 and HNF-3beta. We have demonstrated that N Oct-3 presents a non-cooperative homodimerization on these two additional targets and can also give rise to heterodimers with HNF-3beta.

Down-regulation of nuclear receptor DNA-binding activity by nitric oxide--HNF4 as a model system.

The numerous physiological roles of nitric oxide (NO) are currently the focus of intensive research. A major pathway by which NO mediates its biological effects is via S-nitrosylation of cysteine residues, and a growing body of evidence suggests that transcription factors are critical targets for such S-nitrosylation. Here we review the ability of NO to down-regulate the activity of transcription factors, and in particular nuclear receptors.