Goat RSPO1 over-expression rescues sex-reversal in Rspo1-knockout XX mice but does not perturb testis differentiation in XY or sex-reversed XX mice

RSPO1 is a newly discovered gene involved in sex differentiation. Two goat BAC clones encompassing the RSPO1 gene (gRSPO1) were injected into mouse oocytes and several transgenic lines derived. Both clones induced gRSPO1 over-expression in various tissues, including male and female gonads, with no obvious phenotype and normal sex-ratios. Introgression of the gRSPO1 transgene into a mouse RSPO1 knockout genotype resulted in the rescue of the fertility and the disappearance of the masculinized gonadic features of the females, demonstrating the functionality of the goat protein in a mouse context. On the contrary, over-expression of gRSPO1 within a mSRY or a gSRY-XX genotypes did not interfere with the SRY-induced male phenotype. Laurine Buscara and Fatemeh Montazer-Torbati contributed equally to this work.     

Side chain azasteroids and thiasteroids as sterol methyltransferase inhibitors in ergosterol biosynthesis

The synthesis of some novel azasteroids and thiasteroids based on a pregnan nucleus with a Δ7 double bond in two to five steps from the key aldehyde (3S,20S)-20-formylpregn-7-en-3-yl acetate has been disclosed herein. These compounds were evaluated as potential inhibitors of the enzyme Δ24-sterol methyltransferase (24-SMT), which is a key enzyme in the biosynthesis of ergosterol, and for their effects on the growth of the yeast Yarrowia lipolytica. Most of the side chain modified analogues were recognized as 24-SMT inhibitors, and in particular the 23-azasteroids 5f–5i and the 24-azasteroid 11 showed potent antifungal activity. The target enzyme could be identified unambiguously using an improved whole-cell assay combined with GC–MS analysis of the sterol pattern resulting upon incubation with the inhibitors.     

Structure–activity relationship of antiparasitic and cytotoxic indoloquinoline alkaloids,and their tricyclic and bicyclic analogues

Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-β-carboline, showed the best in vitro activity, with an IC₅₀ value of 0.45 μM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI > 1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure–activity relationships are discussed and compared with related naturally occurring compounds.     

Population structures and individual performances of <Emphasis Type="Italic">Trillium grandiflorum</Emphasis> in hedgerow and forest habitats

In agricultural landscapes, linear habitats, such as hedgerows at field margins increase structural connectivity among forest patches, potentially providing dispersal corridors for forest herbs. The spatial structure of linear habitats, however, also results in edge effects and perturbations that can influence the individual and population performance of forest plants. This study compares the stage structure and components of growth and reproduction of 14 Trillium grandiflorum populations in hedgerows and forests. Hedgerow Trillium tended to grow faster and, when mature, produced more flowers and more ovules per flowers than forest Trillium, a pattern possibly associated to differences in nutrients and light availability between the two habitats. Seed production and germination rate, however, did not differ between hedgerows and forests. At the population level, seedlings and juveniles were proportionally less abundant in hedgerows than in forests. Although well-established plants can thrive in hedgerows, reduced recruitment may eventually limit the capacity to establish new populations and therefore hamper migration along hedgerow-corridors. Considering the strategies by which plants persist in linear habitats becomes particularly relevant at a time when species are expected to be much in need of dispersal corridors because of climatic stress.     

Chromatin Landscapes of Retroviral and Transposon Integration Profiles

The ability of retroviruses and transposons to insert their genetic material into host DNA makes them widely used tools in molecular biology, cancer research and gene therapy. However, these systems have biases that may strongly affect research outcomes. To address this issue, we generated very large datasets consisting of to unselected integrations in the mouse genome for the Sleeping Beauty (SB) and piggyBac (PB) transposons, and the Mouse Mammary Tumor Virus (MMTV). We analyzed (epi)genomic features to generate bias maps at both local and genome-wide scales. MMTV showed a remarkably uniform distribution of integrations across the genome. More distinct preferences were observed for the two transposons, with PB showing remarkable resemblance to bias profiles of the Murine Leukemia Virus. Furthermore, we present a model where target site selection is directed at multiple scales. At a large scale, target site selection is similar across systems, and defined by domain-oriented features, namely expression of proximal genes, proximity to CpG islands and to genic features, chromatin compaction and replication timing. Notable differences between the systems are mainly observed at smaller scales, and are directed by a diverse range of features. To study the effect of these biases on integration sites occupied under selective pressure, we turned to insertional mutagenesis (IM) screens. In IM screens, putative cancer genes are identified by finding frequently targeted genomic regions, or Common Integration Sites (CISs). Within three recently completed IM screens, we identified 7%–33% putative false positive CISs, which are likely not the result of the oncogenic selection process. Moreover, results indicate that PB, compared to SB, is more suited to tag oncogenes.     

Proteomic differences between microvascular endothelial cells and the EA.hy926 cell line forming three‐dimensional structures

Proteomic changes of two types of human endothelial cells (ECs) were determined and compared to morphological alterations occurring during the scaffold‐free in vitro formation of 3D structures resembling vascular intimas. The EA.hy926 cell line and human microvascular ECs (HMVECs) were cultured on a random positioning machine or static on ground (normal gravity) for 5 and 7 days, before their morphology was examined and their protein content was analysed by MS after free‐flow electrophoretic separation. A total of 1175 types of proteins were found in EA.hy926 cells and 846 in HMVEC forming 3D structures faster than the EA.hy926 cells. Five hundred and eighty‐four of these kinds of proteins were present in both types of cells. They included a number of metabolic enzymes, of structure‐related and stress proteins. Comparing proteins of EA.hy926 cells growing either adherently on ground or in 3D aggregates on the random positioning machine revealed that ribosomal proteins were enhanced, while tubes are formed and various components of 26S proteasomes remained prevalent in static normal gravity control cells only. The fast developing tube‐like 3D structures of HMVEC suggested a transient augmentation of ribosomal proteins during the 3D assembling of ECs.     

Succinyl-CoA:(R)-Benzylsuccinate CoA-Transferase: an Enzyme of the Anaerobic Toluene Catabolic Pathway in Denitrifying Bacteria

Anaerobic microbial toluene catabolism is initiated by addition of fumarate to the methyl group of toluene, yielding (R)-benzylsuccinate as first intermediate, which is further metabolized via beta-oxidation to benzoyl-coenzyme A (CoA) and succinyl-CoA. A specific succinyl-CoA:(R)-benzylsuccinate CoA-transferase activating (R)-benzylsuccinate to the CoA-thioester was purified and characterized from Thauera aromatica. The enzyme is fully reversible and forms exclusively the 2-(R)-benzylsuccinyl-CoA isomer. Only some close chemical analogs of the substrates are accepted by the enzyme: succinate was partially replaced by maleate or methylsuccinate, and (R)-benzylsuccinate was replaced by methylsuccinate, benzylmalonate, or phenylsuccinate. In contrast to all other known CoA-transferases, the enzyme consists of two subunits of similar amino acid sequences and similar sizes (44 and 45 kDa) in an alpha(2)beta(2) conformation. Identity of the subunits with the products of the previously identified toluene-induced bbsEF genes was confirmed by determination of the exact masses via electrospray-mass spectrometry. The deduced amino acid sequences resemble those of only two other characterized CoA-transferases, oxalyl-CoA:formate CoA-transferase and (E)-cinnamoyl-CoA:(R)-phenyllactate CoA-transferase, which represent a new family of CoA-transferases. As suggested by kinetic analysis, the reaction mechanism of enzymes of this family apparently involves formation of a ternary complex between the enzyme and the two substrates.