Organization of the early region of bacteriophage phi 80. Genes and proteins

An EcoRI segment containing the early region of bacteriophage phi 80 DNA that controls immunity and lytic growth was identified as a segment whose presence on a plasmid prevented growth of infecting phi 80cI phage. The nucleotide sequence of the segment (EcoRI-F) and adjacent regions was determined. Based on the positions of amber mutations and the sizes of some gene products, the reading frames for five genes were identified. From the relative locations of these genes in the genome, the properties of some isolated gene products, and the analysis of the structures of predicted proteins, the following phi 80 to lambda analogies are deduced: genes cI and cII to their lambda namesakes; gene 30 to cro; gene 15 to O; and gene 14 to P. An amber mutation by which gene 16 was defined is a nonsense mutation in the frame for gene 15 protein, excluding the presence of gene 16. An amber mutation in gene 14 or 15 inhibits phage DNA synthesis, as is the case with their lambda analogues, gene O or P. Some characteristics of proteins from the early region predicted from their primary structures and their possible functions are discussed.     

Dental pulp–derived stem cells inhibit osteoclast differentiation by secreting osteoprotegerin and deactivating AKT signalling in myeloid cells

Osteoclasts (OCs) differentiate from the monocyte/macrophage lineage, critically regulate bone resorption and remodelling in both homeostasis and pathology. Various immune and non-immune cells help initiating activation of myeloid cells for differentiation, whereas hyper-activation leads to pathogenesis, and mechanisms are yet to be completely understood. Herein, we show the efficacy of dental pulp–derived stem cells (DPSCs) in limiting RAW 264.7 cell differentiation and underlying molecular mechanism, which has the potential for future therapeutic application in bone-related disorders. We found that DPSCs inhibit induced OC differentiation of RAW 264.7 cells when co-cultured in a contact-free system. DPSCs reduced expression of key OC markers, such as NFATc1, cathepsin K, TRAP, RANK and MMP-9 assessed by quantitative RT-PCR, Western blotting and immunofluorescence detection methods. Furthermore, quantitative RT-PCR analysis revealed that DPSCs mediated M2 polarization of RAW 264.7 cells. To define molecular mechanisms, we found that osteoprotegerin (OPG), an OC inhibitory factor, was up-regulated in RAW 264.7 cells in the presence of DPSCs. Moreover, DPSCs also constitutively secrete OPG that contributed in limiting OC differentiation. Finally, the addition of recombinant OPG inhibited OC differentiation in a dose-dependent manner by reducing the expression of OC differentiation markers, NFATc1, cathepsin K, TRAP, RANK and MMP9 in RAW 264.7 cells. RNAKL and M-CSF phosphorylate AKT and activate PI3K-AKT signalling pathway during osteoclast differentiation. We further confirmed that OPG-mediated inhibition of the downstream activation of PI3K-AKT signalling pathway was similar to the DPSC co-culture–mediated inhibition of OC differentiation. This study provides novel evidence of DPSC-mediated inhibition of osteoclastogenesis mechanisms.     

Partial Enrichment of Pea Phytochrome mRNA by Gel Electrophoresis and Transfer to Poly (U)-Paper

Total cellular poly(A)⁺RNA from etiolated pea epicotyls wasfractionated by urea-agarose gel electrophoresis and recoveredby transfer to poly(U)-paper. Phytochrome mRNA activity wasdetected in RNA fractions that migrated slightly slower thanthe 25S rRNA in the electrophoresis. A single run of this fractionationenriched the phytochrome mRNA content 20-fold. This techniquetogether with hybridization on poly(U)-paper made it possibleto compare the mobilities of translatable and hybridizable phytochromemRNA. The advantages of the present method of mRNA fractionationin preparing enriched mRNA and identifying cDNA clone are discussed. (Received September 28, 1985; Accepted November 8, 1985)     

Increased frequency of specific alleles of the c-Ha-ras gene in Japanese cancer patients

Summary We have examined the c-Ha-ras locus in 145 cancer patients of a mixed group and 164 normal individuals in Japan for restriction fragment length polymorphisms and compared the allele distributions in normal and cancer populations. The c-Ha-ras gene is highly polymorphic in Japanese as previously reported in Caucasians. Two rare alleles were found to be present with increased frequencies in Japanese cancer patients. These results suggest that genotype analysis of the c-Ha-ras gene could be used to detect cancer-prone individuals.