Inter- and intrapopulational variations in the peroxidase isozyme ofAsarum nipponicum F. Maekawa

Both the inter- and intrapopulational variations in five natural populations ofAsarum nipponicum F. Maekawa were demonstrated for peroxidase isozymes using gel electrofocusing. The patterns of isozymic variation suggested that a very short distance (100 m) effectively isolates populations. The reason why some bands were not detected in a particular population is discussed in terms of genetic drift.     

An epigenetic aberration increased in intergenic regions of cloned mice

The causes of frequent abnormal phenotypes and low success rate in mammalian cloning are poorly understood. Although epigenetic aberration is suspected to be a cause, its connection to the phenotypes has yet to be investigated. To measure the level of reprogramming of an epigenetic mark, acetylation at lysine 9 of histone H3 (H3K9Ac), in cloned mice, we examined its conservation between two cloned mice derived from distinct cell nuclei and their natural donors by utilizing whole-genome tiling arrays and quantitative PCR. Pairwise comparison of the H3K9Ac enrichment profile between the four mice revealed that H3K9Ac is less conserved in intergenic regions than in promoter regions of protein-coding genes. Intriguingly, the variation of H3K9Ac enrichment in intergenic regions is the most prominent in comparison of the two clones, possibly reflecting an additive effect of aberrant reprogramming of this epigenetic information occurring specifically in each of the two clones.

     

A new fluorometric assay method for quinolinic acid

A new fluorometric assay method for quinolinic acid is introduced in this study. Quinolinic acid-hydrazine complex, a stable fluorescent compound, is formed after heating quinolinic acid with hydrazine at 215–220°C for 2 min. Fluorescence excitation and emission maxima of the complex are at 285 and 380 nm, respectively. This assay method is rapid and rather sensitive. It takes about 30 min to ascertain the amount of quinolinic acid as low as 50 ng. Specificity of this method is high among biological compounds. An ultrasensitive assay method for uinolinic acid (as low as 20 pg) with diphenylhydrazine instead of hydrazine is also found. After separating the quinolinic acid-diphenylhydrazine complex from residual diphenylhydrazine, this ultrasensitive assay method may be practically applicable.     

Simplified ontologies allowing comparison of developmental mammalian gene expression

Model organisms represent an important resource for understanding the fundamental aspects of mammalian biology. Mapping of biological phenomena between model organisms is complex and if it is to be meaningful, a simplified representation can be a powerful means for comparison. The Developmental eVOC ontologies presented here are simplified orthogonal ontologies describing the temporal and spatial distribution of developmental human and mouse anatomy. We demonstrate the ontologies by identifying genes showing a bias for developmental brain expression in human and mouse.     

Solution structure of the kinase-associated domain 1 of mouse microtubule-associated protein/microtubule affinity-regulating kinase 3

Microtubule-associated protein/microtubule affinity-regulating kinases (MARKs)/PAR-1 are common regulators of cell polarity that are conserved from nematode to human. All of these kinases have a highly conserved C-terminal domain, which is termed the kinase-associated domain 1 (KA1), although its function is unknown. In this study, we determined the solution structure of the KA1 domain of mouse MARK3 by NMR spectroscopy. We found that approximately 50 additional residues preceding the previously defined KA1 domain are required for its proper folding. The newly defined KA1 domain adopts a compact alpha+beta structure with a betaalphabetabetabetabetaalpha topology. We also found a characteristic hydrophobic, concave surface surrounded by positively charged residues. This concave surface includes the highly conserved Glu-Leu-Lys-Leu motif at the C terminus, indicating that it is important for the function of the KA1 domain.     

Nanoscale elongating control of the self‐assembled protein filament with the cysteine‐introduced building blocks

Self‐assembly of artificially designed proteins is extremely desirable for nanomaterials. Here we show a novel strategy for the creation of self‐assembling proteins, named “Nanolego.” Nanolego consists of “structural elements” of a structurally stable symmetrical homo‐oligomeric protein and “binding elements,” which are multiple heterointeraction proteins with relatively weak affinity. We have established two key technologies for Nanolego, a stabilization method and a method for terminating the self‐assembly process. The stabilization method is mediated by disulfide bonds between Cysteine‐residues incorporated into the binding elements, and the termination method uses “capping Nanolegos,” in which some of the binding elements in the Nanolego are absent for the self‐assembled ends. With these technologies, we successfully constructed timing‐controlled and size‐regulated filament‐shape complexes via Nanolego self‐assembly. The Nanolego concept and these technologies should pave the way for regulated nanoarchitecture using designed proteins.