The translation attenuating arginine-rich sequence in the extended signal peptide of the protein-tyrosine phosphatase PTPRJ/DEP1 is conserved in mammals.

The signal peptides, present at the N-terminus of many proteins, guide the proteins into cell membranes. In some proteins, the signal peptide is with an extended N-terminal region. Previously, it was demonstrated that the N-terminally extended signal peptide of the human PTPRJ contains a cluster of arginine residues, which attenuates translation.

The Hordeum bulbosum 25S-18S rDNA region: comparison with Hordeum vulgare and other Triticeae.

Hordeum vulgare and Hordeum bulbosum are two closely related barley species, which share a common H genome. H. vulgare has two nucleolar organizer regions (NORs), while the NOR of H.

Mapping of unmethylated sites in rDNA repeats in barley NOR deletion line.

Extensive cytosine methylation is characteristic of plant rDNA. Evidence exists, however, that the active rRNA genes are less methylated. In this work we report on the mapping of unmethylated CCGG sites in Hordeum vulgare rDNA repeats by digestion with methylation sensitive restriction enzyme HpaII and indirect end-labeling of the generated fragments.

The structure of the 5'-end of the protein-tyrosine phosphatase PTPRJ mRNA reveals a novel mechanism for translation attenuation.

Analysis of the human protein-tyrosine phosphatase (PTP) PTPRJ mRNA detected three in-frame AUGs at the 5'-end (starting at nt +14, +191 and +356) with no intervening stop codons. This tandem AUG arrangement is conserved between humans and the mouse and is unique among the genes of the classical PTPs. Until now it was assumed that the principal open reading frame (ORF) starts at AUG(356).

Discovery of novel inhibitors targeting enoyl-acyl carrier protein reductase in Plasmodium falciparum by structure-based virtual screening.

There is a dire need for novel therapeutics to treat the virulent malarial parasite, Plasmodium falciparum. Recently, the X-ray crystal structure of enoyl-acyl carrier protein reductase (ENR) in complex with triclosan has been determined and provides an opportunity for the rational design of novel inhibitors targeting the active site of ENR. Here, we report the discovery of several compounds by virtual screening and their experimental validation as high potency PfENR inhibitors.

Synthesis and biological activity of diaryl ether inhibitors of malarial enoyl acyl carrier protein reductase. Part 2: 2'-substituted triclosan derivatives.

2'-Substituted analogs of triclosan have been synthesized to target inhibition of the key malarial enzyme Plasmodium falciparum enoyl acyl carrier protein reductase (PfENR). Many of these compounds exhibit good potency (EC50<500 nM) against in vitro cultures of drug-resistant and drug-sensitive strains of the P. falciparum parasite and modest (IC50=1-20 microM) potency against purified PfENR enzyme.

Expression and localization of PCSK9 in rat hepatic cells.

Proprotein convertase subtilisin/kexin type 9 (PCSK9), recently cloned in several laboratories, including ours, causes a third form of autosomal dominant hypercholesterolemia. Its mechanism of action remains unclear. We studied the expression and subcellular localization of PCSK9 in fetal and adult rat tissues associated with cholesterol homeostasis using quantitative reverse transcriptase--PCR, Western blot analysis, subcellular fractionation, and confocal immunofluorescent microscopy.

Complete sequence of the 45-kb mouse ribosomal DNA repeat: analysis of the intergenic spacer.

DNA from a single bacterial artificial chromosome clone was used to sequence the mouse ribosomal DNA intergenic spacer from the 3' end of the 45S pre-RNA to the spacer promoter (Accession No. AF441733). This made possible the assembly of a complete mouse ribosomal DNA repeat unit (45309 bp long, TPA Accession No.

Silencing of retroviral vector transduced LacZ reporter gene by frameshift mutation.

Moloney murine leukemia virus-based vector expressing Escherichia coli beta-galactosidase (lacZ) as reporter gene and the transposon Tn5 neomycin resistance (neo) gene was transduced at low-multiplicity of infections into NIH 3T3 cells. Geneticin (G418)-resistant cells were recloned and cell lines containing beta-galactosidase positive or beta-galactosidase negative cells were obtained. Both positive and negative cell lines contained a single proviral copy at distinct integration sites.

The mouse ribosomal DNA amplification promoting sequence 1 is highly methylated and repeated in the genome.

Upstream of the mouse 45S pre-ribosomal RNA promoter there are regions that are involved in enhancement of pre-rRNA transcription, origin of replication and promotion of amplification. We report that in different mouse strains and cell lines the enhancer region, which overlaps with the origin of replication, is hypo-methylated. Contrary to that the amplification-promoting sequences 1 and 2, identified upstream in the intergenic spacer, are hypermethylated.

A single amino acid exchange inverts susceptibility of related receptor tyrosine kinases for the ATP site inhibitor STI-571.

The tyrosine kinase inhibitor STI-571 potently blocks BCR-Abl, platelet-derived growth factor (PDGF) alpha- and beta-receptors, and c-Kit kinase activity. Flt3, a receptor tyrosine kinase closely related to PDGF receptors and c-Kit is, however, not inhibited by STI-571. Sequence alignments of different kinases and indications from the crystal structure of the STI-571 Abl kinase complex revealed amino acid residues that are probably crucial for this activity profile.

Hereditary motor and sensory neuropathy--Lom (HMSNL): refined genetic mapping in Romani (Gypsy) families from several European countries.

Hereditary motor and sensory neuropathy type Lom, initially identified in Roma (Gypsy) families from Bulgaria, has been mapped to 8q24. Further refined mapping of the region has been undertaken on DNA from patients diagnosed across Europe. The refined map consists of 25 microsatellite markers over approximately 3 cM.

Binding of histones to Xenopus laevis ribosomal genes with different levels of expression.

The association of ribosomal RNA genes with histones as a function of their expression has been studied in Xenopus laevis erythrocytes, where the genes are silent, and tadpoles at stage 40, where these genes are actively transcribed. Isolated nuclei were either treated with formaldehyde or irradiated with an ultraviolet laser to cross-link proteins to DNA. The covalently linked protein-DNA complexes were purified by centrifugation through CsCl and immunoprecipitated with antibodies against H1, H2A and H4.

Transcription of ribosomal DNA intergenic spacer sequences in normal and regenerating rat liver.

In regenerating rat liver both the transcriptional activity of the intergenic spacer rDNA promoter and the steady-state abundance of spacer transcripts are increased about 2-fold, as compared to normal liver. These changes are parallel to the observed 2.5-fold increase in regenerating liver of rRNA gene promotor activity and gene promotor transcripts abundance.

The enhancers and promoters of the Xenopus laevis ribosomal spacer are associated with histones upon active transcription of the ribosomal genes.

The presence of histones on the enhancer-promoter region of the X.laevis ribosomal spacer has been studied in embryos at stage 40, where the ribosomal genes are actively transcribed. Isolated tadpole nuclei were either fixed with formaldehyde or irradiated with UV laser to crosslink histones to DNA.

Chronic ethanol treatment of rats reduces RNA polymerase activity in isolated liver nuclei.

The effect of acute and chronic ethanol treatment of rats on the activity of RNA polymerases I and II in isolated nuclei has been studied. Results indicate that acute ethanol administration does not change the activity of the nuclear RNA polymerases while chronic ethanol treatment significantly reduces the activity of both RNA polymerases I and II.

Effect of cytokinins on ribosomal RNA gene expression in excised cotyledons of Cucurbita pepo L.

Excised pumpkin (Cucurbita pepo L.) cotyledons were used to investigate the effects of two different types of cytokinins: N(6)-benzyladenine and N1-(2-chloro-4-pyridyl)-N2-phenylurea on RNA synthesis in isolated nuclei. Treatment of cotyledons with both cytokinins resulted in a rapid enhancement of nuclear RNA-polymerase-I activity (EC 2.

Isolation of active transcription complexes from animal cell nuclei by nitrocellulose binding.

A method for the rapid isolation of active transcription complexes from animal cell nuclei is described. The method is based on the observation that, after lysis of nuclei with the detergents Sarkosyl and Triton X-100, transcription complexes are selectively bound to nitrocellulose. The nitrocellulose filters retain 80-90% o the RNA labelled briefly in vitro and about 10% of the nuclear DNA.

Effect of cycloheximide on the in vivo and in vitro synthesis of ribosomal RNA in rat liver.

The action of low (5 mg/kg body wt;) and high (20 mg/kg body wt.) doses of cycloheximide, both causing a rapid and almost complete inhibition of protein synthesis in rat liver is investigated. Short-term (15 min) [14C]orotate incorporation into nucleolar rRNA in vivo is inhibited only by the high dose acting for periods longer than 1 h.

Transcription of DNA-histone complexes by yeast RNA polymerase B.

Transcription of denatured DNA complexed with histones (total, H1 or H2A/H2B/H3/H4) by yeast RNA polymerase B is investigated. Binding of histones to DNA restricts its template activity by decreasing the formation of active, heparin-resistant, RNA polymerase initiation complexes. The elongation of pre-initiated RNA on denatured DNA, complexed with histones, is possible, although resulting in somewhat shorter RNA chains.