Asymmetric dimerization in a transcription factor superfamily is promoted by allosteric interactions with DNA.

Transcription factors, such as nuclear receptors achieve precise transcriptional regulation by means of a tight and reciprocal communication with DNA, where cooperativity gained by receptor dimerization is added to binding site sequence specificity to expand the range of DNA target gene sequences. To unravel the evolutionary steps in the emergence of DNA selection by steroid receptors (SRs) from monomeric to dimeric palindromic binding sites, we carried out crystallographic, biophysical and phylogenetic studies, focusing on the estrogen-related receptors (ERRs, NR3B) that represent closest relatives of SRs. Our results, showing the structure of the ERR DNA-binding domain bound to a palindromic response element (RE), unveil the molecular mechanisms of ERR dimerization which are imprinted in the protein itself with DNA acting as an allosteric driver by allowing the formation of a novel extended asymmetric dimerization region (KR-box).

Measure for Chaotic Scattering Amplitudes.

We propose a novel measure of chaotic scattering amplitudes. It takes the form of a log-normal distribution function for the ratios r_{n}=δ_{n}/δ_{n+1} of (consecutive) spacings δ_{n} between two (consecutive) peaks of the scattering amplitude. We show that the same measure applies to the quantum mechanical scattering on a leaky torus as well as to the decay of highly excited string states into two tachyons.

Organic matrices in metazoan calcium carbonate skeletons: Composition, functions, evolution.

Calcium carbonate skeletal tissues in metazoans comprise a small quantity of occluded organic macromolecules, mostly proteins and polysaccharides that constitute the skeletal matrix. Because its functions in modulating the biomineralization process are well known, the skeletal matrix has been extensively studied, successively via classical biochemical approaches, via molecular biology and, in recent years, via transcriptomics and proteomics. The optimistic view that the deposition of calcium carbonate minerals requires a limited number of macromolecules has been challenged, in the last decade, by high-throughput approaches.

The deuterostome context of chordate origins.

Our understanding of vertebrate origins is powerfully informed by comparative morphology, embryology and genomics of chordates, hemichordates and echinoderms, which together make up the deuterostome clade. Striking body-plan differences among these phyla have historically hindered the identification of ancestral morphological features, but recent progress in molecular genetics and embryology has revealed deep similarities in body-axis formation and organization across deuterostomes, at stages before morphological differences develop. These developmental genetic features, along with robust support of pharyngeal gill slits as a shared deuterostome character, provide the foundation for the emergence of chordates.