Prostate stem cell antigen is an endogenous lynx1-like prototoxin that antagonizes α7-containing nicotinic receptors and prevents programmed cell death of parasympathetic neurons

Vertebrate alpha-bungarotoxin-like molecules of the Ly-6 superfamily have been implicated as balancers of activity and survival in the adult nervous system. To determine whether a member of this family could be involved in the development of the avian ciliary ganglion, we identified 6 Gallus genes by their homology in structure to mouse lynx1 and lynx2. One of these genes, an ortholog of prostate stem cell antigen (psca), is barely detectable at embryonic day (E) 8, before neuronal cell loss in the ciliary ganglion, but increases >100-fold as the number of neurons begins to decline between E9 and E14. PSCA is highly expressed in chicken and mouse telencephalon and peripheral ganglia and correlates with expression of alpha7-containing nicotinic acetylcholine receptors (alpha7-nAChRs). Misexpressing PSCA before cell death in the ciliary ganglion blocks alpha7-nAChR activation by nicotine and rescues the choroid subpopulation from dying. Thus, PSCA, a molecule previously identified as a marker of prostate cancer, is a member of the Ly-6 neurotoxin-like family in the nervous system, and is likely to play a role as a modulator of alpha7 signaling-induced cell death during development

Selection of Bread Wheat for Low Grain Cadmium Concentration at the Seedling Stage Using Hydroponics versus Molecular Markers

The excessive accumulation of Cd in harvested crops grown on high-Cd soils has increased public concerns for food safety. Due to the high consumption of bread wheat (Triticum aestivum L.) per capita, high concentrations of Cd in wheat grain can significantly affect human health. Breeding is a promising way to reduce grain Cd concentration. However, a lack of efficient selection methods impedes breeding for low grain Cd concentration in bread wheat. In this study, a recombinant inbred population segregating for grain Cd concentration was used to assess the efficacy of two selection methods for decreasing grain Cd concentration in bread wheat: a hydroponic selection method used shoot Cd concentration in 2-wk-old seedlings growing in Cd-containing medium, and a marker-based selection method using markers linked to heavy metal transporting P1B-ATPase 3 (HMA3), the gene underlying Cdu1. Both methods effectively selected low-Cd lines. The HMA3-linked marker-based selection was superior to hydroponic selection in terms of both simplicity and response to selection. The HMA3-linked markers explained 20% of the phenotypic variation in grain Cd concentration with an additive effect of 0.014 mg kg−1. The hydroponic selection and marker-based selection may target two different and independent processes controlling grain Cd accumulation, and they had no effect on grain Zn and Fe concentrations. The ALMT1-UPS4 marker associated with Al tolerance was not associated with grain Cd concentration but increased grain Zn and Fe concentrations. The 193-bp allele of the Rht8-associated marker, GWM261, was associated with increased grain Cd concentration

Cytochrome P450 20A1 in zebrafish: Cloning, regulation and potential involvement in hyperactivity disorders

Cytochrome P450 (CYP) enzymes for which there is no functional information are considered "orphan" CYPs. Previous studies showed that CYP20A1, an orphan, is expressed in human hippocampus and substantia nigra, and in zebrafish (Danio rerio) CYP20A1 maternal transcript occurs in eggs, suggesting involvement in brain and in early development. Moreover, hyperactivity is reported in humans with chromosome 2 microdeletions including CYP20A1. We examined CYP20A1 in zebrafish, including impacts of chemical exposure on expression. Zebrafish CYP20A1 cDNA was cloned, sequenced, and aligned with cloned human CYP20A1 and predicted vertebrate orthologs. CYP20A1s share a highly conserved N-terminal region and unusual sequences in the I-helix and the heme-binding CYP signature motifs. CYP20A1 mRNA expression was observed in adult zebrafish organs including the liver, heart, gonads, spleen and brain, as well as the eye and optic nerve. Putative binding sites in proximal promoter regions of CYP20A1s, and response of zebrafish CYP20A1 to selected nuclear and xenobiotic receptor agonists, point to up-regulation by agents involved in steroid hormone response, cholesterol and lipid metabolism. There also was a dose-dependent reduction of CYP20A1 expression in embryos exposed to environmentally relevant levels of methylmercury. Morpholino knockdown of CYP20A1 in developing zebrafish resulted in behavioral effects, including hyperactivity and a slowing of the optomotor response in larvae. The results suggest that altered expression of CYP20A1 might be part of a mechanism linking methylmercury exposure to neurobehavioral deficits. The expanded information on CYP20A1 brings us closer to "deorphanization" CYP20A1 functions and its roles in health and disease

Chemical proteomics approaches for identifying the cellular targets of natural products.

Covering: 2010 up to 2016. Deconvoluting the mode of action of natural products and drugs remains one of the biggest challenges in chemistry and biology today. Chemical proteomics is a growing area of chemical biology that seeks to design small molecule probes to understand protein function. In the context of natural products, chemical proteomics can be used to identify the protein binding partners or targets of small molecules in live cells. Here, we highlight recent examples of chemical probes based on natural products and their application for target identification. The review focuses on probes that can be covalently linked to their target proteins (either via intrinsic chemical reactivity or via the introduction of photocrosslinkers), and can be applied "in situ" - in living systems rather than cell lysates. We also focus here on strategies that employ a click reaction, the copper-catalysed azide-alkyne cycloaddition reaction (CuAAC), to allow minimal functionalisation of natural product scaffolds with an alkyne or azide tag. We also discuss 'competitive mode' approaches that screen for natural products that compete with a well-characterised chemical probe for binding to a particular set of protein targets. Fuelled by advances in mass spectrometry instrumentation and bioinformatics, many modern strategies are now embracing quantitative proteomics to help define the true interacting partners of probes, and we highlight the opportunities this rapidly evolving technology provides in chemical proteomics. Finally, some of the limitations and challenges of chemical proteomics approaches are discussed

The cortistatin gene PSS2 rather than the somatostatin gene PSS1 is strongly expressed in developing avian autonomic neurons

Somatostatin and cortistatin are neuromodulators with divergent expression patterns and biological roles. Whereas expression and function of genes encoding somatostatin (PSS1) and the related peptide cortistatin (PSS2) have been studied in detail for the central nervous system (CNS) and immune system, relatively little is known about their expression patterns in the peripheral nervous system (PNS). We compare the expression patterns of PSS1 and PSS2 in chicken embryos. At E14, PSS1 is higher in the CNS versus PNS, whereas PSS2 is higher in the PNS. During early development, PSS1 is transiently expressed in lumbar sympathetic ganglia and is detectable at low levels throughout the development of dorsal root and ciliary ganglia. In contrast, PSS2 expression increases as development progresses in sympathetic and dorsal root ganglia, whereas levels in ciliary ganglia by E8 are more than 100-fold higher than in sympathetic ganglia. Activin, which induces somatostatin-like immunoreactivity in ciliary ganglion neurons in vivo and in vitro, controls PSS2 expression by stabilizing PSS2 but not PSS1 mRNA. We conclude that much of the somatostatin-like immunoreactivity in the developing avian peripheral nervous system is actually cortistatin, the PSS2 product, as opposed to true somatostatin, which is the PSS1 product. The identification of PSS2 as the predominantly expressed somatostatin gene family member in avian autonomic neurons provides a molecular basis for further functional and pharmacological studies. J. Comp. Neurol. 518:839 - 850, 2010. (C) 2009 Wiley-Liss, Inc