A farnesyl arabinoside as an enhancer of glucose transport in rat adipocytes from a soft coral, Sinularia sp.

Separation of a lipophilic extract of a soft coral, Sinularia sp., assayed by enhancement of glucose transport in rat adipocytes, gave farnesyl 4-O-beta-D-arabinopyranosyl-beta-D-arabinopyranoside-2,2',3- triacetate (1a) whose structure was determined by spectroscopy. Enhancers of glucose transport may be useful for the prevention and treatment of diabetic disorders.     

Cloning and structure of a yeast gene encoding a general transcription initiation factor TFIID that binds to the TATA box

The TATA sequence-binding factor TFIID plays a central role both in promoter activation by RNA polymerase II and other common initiation factors, and in promoter regulation by gene-specific factors. The sequence of yeast TFIID, which seems to be encoded by a single gene, contains interesting structural motifs that are possibly involved in these functions, and is similar to sequences of bacterial sigma factors.     

The triangular halophilic archaebacteriumHaloarcula japonica strain TR-1

We have isolated a predominantly triangular disc-shaped halophilic archaebacterium, strain TR-1, from a Japanese saltern soil. The taxonomical characteristics of this strain led us to propose a new speciesHaloarcula japonica. The cell division ofHa. japonica strain TR-1 was analyzed by time lapse microscopic cinematography. Cell plates were laid down asymmetrically, generating triangular or rhombic daughter cells which then separated. We have demonstrated the occurrence of a glycoprotein with an apparent molecular mass of 170 kDa on the cell surface ofHa. japonica. The release of this cell surface glycoprotein (CSG), accompanied by a morphological change (triangular to spherical), was observed after lowering the magnesium concentration in the medium. Thus, it is likely that the CSG plays an important role in maintaining the characteristic shape ofHa. japonica.     

Histone chaperones: 30 years from isolation to elucidation of the mechanisms of nucleosome assembly and disassembly

Some three decades have passed since the discovery of nucleosomes in 1974 and the first isolation of a histone chaperone in 1978. While various types of histone chaperones have been isolated and functionally analyzed, the elementary processes of nucleosome assembly and disassembly have been less well characterized. Recently, the tertiary structure of a hetero-trimeric complex composed of the histone chaperone CIA/ASF1 and the histone H3-H4 dimer was determined, and this complex was proposed to be an intermediate in nucleosome assembly and disassembly reactions. In addition, CIA alone was biochemically shown to dissociate the histone (H3-H4)₂ tetramer into two histone H3-H4 dimers. This activity suggested that CIA regulates the semi-conservative replication of nucleosomes. Here, we provide an overview of prominent histone chaperones with the goal of elucidating the mechanisms that preserve and modify epigenetic information. We also discuss the reactions involved in nucleosome assembly and disassembly. Received 5 July 2007; received after revision 8 September 2007; accepted 13 September 2007 M. Eitoku, L. Satoa: These authors contributed equally to this work.