Nonspecific DNA binding activity of simian virus 40 large T antigen: evidence for the cooperation of two regions for full activity.

We generated a series of COOH-terminal truncated simian virus 40 large tumor (T) antigens by using oligonucleotide-directed site-specific mutagenesis. The mutant proteins [T(1-650) to T(1-516)] were expressed in insect cells infected with recombinant baculoviruses. T(1-623) and shorter proteins [T(1-621) to T(1-516)] appeared to be structurally changed in a region between residues 269 and 522, as determined by increased sensitivities to trypsin digestion and by altered reactivities to several monoclonal antibodies. These same mutant proteins bound significantly less nonorigin plasmid DNA (15%) and calf thymus DNA (25%) than longer proteins [T(1-625) to T(1-708)]. However, all mutant T antigens exhibited a nearly wild-type level of viral origin-specific DNA binding and binding to a helicase substrate DNA. This indicated that binding to origin and helicase substrate DNAs is separable from about 85% of nonspecific binding to double-stranded DNA. As an independent confirmation that a region distinct from the origin-binding domain (amino acids 147 to 247) is involved in nonspecific DNA binding, we found that up to 96% of this latter activity was specifically inhibited in wild-type T antigen by several monoclonal antibodies which collectively bind to the region between residues 269 and 522. In order to investigate the relationship between the origin-binding domain and the second region, we performed origin-specific DNA binding assays with increasing amounts of calf thymus DNA as competitor. The results suggest that this second region is not an independent nonspecific DNA binding domain. Rather, it most likely cooperates with the origin-binding domain to give rise to wild-type levels of nonspecific DNA binding. Our results further suggest that most of the nonspecific binding to double-stranded DNA is involved in a function other than direct recognition and binding to the pentanucleotides at the replication origin on simian virus 40 DNA.     

Phosphorylation and biosynthesis of high molecular weight proteins of tumor nuclear matrix

INTRODUCTIONAsearlyasin1948wehavefr8CtionatedisolatednucleifromnormalandtumorcellsbyextractionwithiMNaCIanddilutealkali[1].Thenuclearresiduewasthenstudiedmorethoroughly[2,3].Lateron,sillillarproteinousnuclearresidueswereisolatedbyotherworkers[46]andasstud…     

Leaf flavonoids as systematic characters in the genera Lavandula and Sabaudia

A comprehensive survey of the leaf flavonoids of the genus Lavandula and the related Sabaudia group was carried out using two-dimensional paper chromatography and high-performance liquid chromatography. The flavonoid patterns obtained were found to be systematically informative at the infrageneric level. Three main groupings were identified: the first containing sections Lavandula, Dentata and Stoechas characterised by the accumulation of flavone 7-glycosides; the second containing sections Pterostoechas, Subnuda and Chaetostachys characterised by the accumulation of 8-hydroxylated flavone 7-and 8-glycosides; the third encompassing the Sabaudia group and accumulating both flavone and 8-hydroxylated flavone 7- glycosides. Such a grouping of taxa is congruent with data from other disciplines, although it is not recognised in any present classifications. The taxonomic and evolutionary implications of the flavonoid data are discussed.     

Multiple, non-allelic, intein-coding sequences in eukaryotic RNA polymerase genes

Background  

Inteins are self-splicing protein elements. They are translated as inserts within host proteins that excise themselves and ligate the flanking portions of the host protein (exteins) with a peptide bond. They are encoded as in-frame insertions within the genes for the host proteins. Inteins are found in all three domains of life and in viruses, but have a very sporadic distribution. Only a small number of intein coding sequences have been identified in eukaryotic nuclear genes, and all of these are from ascomycete or basidiomycete fungi.     

A novel chemogenomics analysis of G protein-coupled receptors (GPCRs) and their ligands: a potential strategy for receptor de-orphanization

Background  

G protein-coupled receptors (GPCRs) represent a family of well-characterized drug targets with significant therapeutic value. Phylogenetic classifications may help to understand the characteristics of individual GPCRs and their subtypes. Previous phylogenetic classifications were all based on the sequences of receptors, adding only minor information about the ligand binding properties of the receptors. In this work, we compare a sequence-based classification of receptors to a ligand-based classification of the same group of receptors, and evaluate the potential to use sequence relatedness as a predictor for ligand interactions thus aiding the quest for ligands of orphan receptors.     

782. EMMENOPTERYS HENRYI

The Chinese tree Emmenopterys henryi is described and illustrated based on the rare blooming of a specimen at Cambridge University Botanic Garden in summer 2012. Other known flowerings in cultivation are reviewed with particular reference to Britain. The origin of the Cambridge tree, propagated from an original introduction at the Royal Botanic Gardens, Kew and distributed in the early 1980s is discussed. Based on original herbarium collections and archive material the discovery and introduction of this species into cultivation is reviewed.     

Effects of blinding on the ultrastructure of mouse pinealocytes with particular emphasis on the dense-cored vesicles

Summary The mammalian pineal is thought to produce an antigonadotropic principle under conditions of reduced photoperiod, constant darkness or blinding by optic enucleation. A number of previous studies on mammalian pineals have suggested that the dense-cored vesicles present in pinealocytes may represent morphological evidence of secretory activity.In the present study the ultrastructure of pinealocytes was studied in adult Charles River CD-1 mice blinded by optical enucleation. By one month following optic enucleation the mean number of dense-cored vesicles in the cytoplasm of pinealocytes adjacent to pericapillary spaces had significantly decreased by 55% when compared with intact controls, and remained at this low level at two months and six months. A relative increase in the proportion of large agranular vesicles and an increased number of large, irregular vacuoles was observed also in the pinealocytic polar processes of blinded mice. When compared to control mice the pinealocytic Golgi regions appeared to be hypertrophied in blinded mice. The apparent stimulation of pinealocytic organelles coupled with the observed decrease in dense-cored vesicles suggest an increased synthesis and release of secretory product.Supported in part by NIH Grant No. HD 08759     

780. TETRADIUM DANIELLII

The genus Tetradium Lour. is discussed with special reference to taxa in cultivation and the most widely planted species, Tetradium daniellii, (commonly called Euodia daniellii (Benn.) Hemsl. or E. hupehensis Dode) which is the subject of this plate. Its variation, synonymy, history and cultivation are reviewed.