PON1 (paraoxonase-1) detoxifies organophosphates by cleavage of active oxons before they have a chance to inhibit cholinesterases. The corresponding gene PON1 has common polymorphisms in both the promoter (-909, -162, -108) and the coding region (L55M, Q192R). The five PON1 genotypes were determined for maternal blood (n = 402) and cord blood (n = 229) as part of a study of the effects of organophosphate pesticide exposure on infant growth and neurodevelopment. PON1 enzymatic activities were determined for a majority of subjects. The population contained Caucasians, Caribbean Hispanics, and African Americans. PON1 activity was strongly dependent upon the promoter alleles in both maternal and cord blood. For example, PON1 activities for position -108CC, CT, and TT mothers were 146, 128, and 109 arylesterase U/mL (analysis of variance, p < 0.0001), whereas the same PON1 activities for the respective cord bloods were 49.0, 32.4, and 23.2 U/mL (p < 0.0001). Compared with adults, neonates had lower PON1 activity, implying reduced capacity to detoxify organophosphates. In addition there was a larger difference in activity between genotype groups in neonates than in adults. Because the five polymorphisms in PON1 occur in a short stretch of DNA, they were tested for linkage disequilibrium (LD). Significant LD was found among all three promoter polymorphisms as well as between promoter polymorphisms and L55M, with the strongest LD for Caucasians and the weakest for African Americans. The Caribbean Hispanics fall between these two groups. Surprisingly, significant LD also was observed between the promoter polymorphisms and C311S in PON2. LD between the promoter polymorphisms and Q192R was not significant.

Serine racemase (SR) generates D-serine, a coagonist with glutamate at NMDA receptors. We show that SR is physiologically S-nitrosylated leading to marked inhibition of enzyme activity. Inhibition involves interactions with the cofactor ATP reflecting juxtaposition of the ATP-binding site and cysteine-113 (C113), the site for physiological S-nitrosylation. NMDA receptor physiologically enhances SR S-nitrosylation by activating neuronal nitricoxide synthase (nNOS) . These findings support a model whereby postsynaptic stimulation of nitric-oxide (NO) formation feeds back to presynaptic cells to S-nitrosylate SR and decrease D-serine availability to postsynaptic NMDA receptors.neuronal nitric-oxide synthase ͉ NMDA receptor ͉ S-nitrosylation G lutamate neurotransmission through NMDA receptors requires a coagonist originally thought to be glycine. Recent studies indicate that in most portions of the brain, D-serine is the physiological coagonist because selective degradation of D-serine but not glycine markedly reduces NMDA transmission (1, 2), whereas retraction of D-serine-producing glia in the hypothalamus of lactating rats also diminishes NMDA transmission (2). D-serine is formed from L-serine by serine racemase (SR), which, like D-serine, is selectively enriched in glia (2, 3), although recent studies indicate some neuronal localization (4). SR, a pyridoxal phosphate-requiring enzyme, also displays an absolute requirement for ATP, which is not hydrolyzed during SR activation (5). SR binds the glutamate receptor interacting protein, which also binds to AMPA subtypes of glutamate receptors with glutamate receptor interacting protein markedly activating SR and providing a means whereby glutamate stimulation of SR-containing cells augments D-serine formation (6).In postsynaptic cells, NMDA signaling is mediated in part by neuronal nitric-oxide synthase (nNOS) because calcium entering through NMDA receptor channels binds to calmodulin associated with nNOS (7,8). Extensive studies have documented a feedback from postsynaptic to presynaptic glutamatergic nerve terminals, which modulates NMDA neurotransmission, especially in long-term potentiation (9). Nitric oxide (NO) may be a retrograde messenger of long-term potentiation (10-12), although the area is controversial (12). Because SR is a component of the NMDA synaptic complex, we wondered whether it is influenced by NO. In the present study, we demonstrate that SR is physiologically S-nitrosylated leading to inhibition of enzyme activity mediated by interactions with ATP. NMDA transmission stimulates SR S-nitrosylation suggesting a feedback mechanism to diminish presynaptic formation of D-serine. ResultsWe demonstrated S-nitrosylation of SR in multiple ways. Incubation of the NO donor S-nitroso-glutathione (GSNO) with SR in vitro leads to robust nitrosylation (Fig. 1A). In HEK293 cells, treatment with the NO donor sodium nitroprusside also provides S-nitrosylation (Fig. 1B). NO produced by nNOS S-nitrosylates SR, as is evident in HEK293 cells transfected with nNOS (Fi...

The induction of interferon beta (IFNB1) is a key event in the antiviral immune response. We studied the role of transcriptional noise in the regulation of the IFNB1 locus in primary cultures of human dendritic cells (DCs), which are important ‘first responders’ to viral infection. In single cell assays, IFNB1 mRNA expression in virus-infected DCs showed much greater cell-to-cell variation than that of a housekeeping gene, another induced transcript and viral RNA. We determined the contribution of intrinsic noise by measuring the allelic origin of transcripts in each cell and found that intrinsic noise is a very significant part of total noise. We developed a stochastic model to investigate the underlying mechanisms. We propose that the surprisingly high levels of IFNB1 transcript noise originate from the complexity of IFNB1 enhanceosome formation, which leads to a range up to many minutes in the differences within each cell in the time of activation of each allele.

We have isolated a homolog of the cell division gene ftsZ from the extremely halophilic archaebacterium Halobacterium salinarium. The predicted protein of 39 kDa is divergent relative to eubacterial homologs, with 32% identity to Escherichia coli FtsZ. No other eubacterial cell division gene homologs were found adjacent to H. salinarium ftsZ. Expression of the ftsZ gene region in H. salinarium induced significant morphological changes leading to the loss of rod shape. Phylogenetic analysis demonstrated that the H. salinarium FtsZ protein is more related to tubulins than are the FtsZ proteins of eubacteria, supporting the hypothesis that FtsZ may have evolved into eukaryotic tubulin.FtsZ is an essential cell division protein in Escherichia coli and Bacillus subtilis (3, 9) and appears to be conserved among eubacteria (8). It polymerizes to form a circumferential ring at the division site, constricting at the leading edge of the invaginating septum that will eventually separate the two daughter cells (6,26). FtsZ both shares biochemical properties with and has structural similarities to eukaryotic tubulins. Both bind and hydrolyze GTP, polymerize to form tubules in a GTP-dependent manner, and are involved in cytoskeletal processes in the cell during cell division (7,10,31,32,37). All identified FtsZ proteins from eubacteria contain a conserved N terminus that carries the tubulin-like GTP-binding motif and a hydrophilic, variable C terminus.Although the role of FtsZ in cytokinesis differs from the actin-mediated cytokinesis in eukaryotic cells, the biochemical and amino acid sequence data have led to the proposal that FtsZ is a prokaryotic version of tubulin (14). Since the origins of the eukaryotic cytoskeleton are unknown, an intriguing hypothesis is that FtsZ evolved into tubulin. Since it is believed that the archaea and eucarya diverged after the divergence of archaea from bacteria, then identification of an FtsZ protein in an archaebacterial species might shed light on this evolutionary question (18,21). Because archaebacteria in general have a prokaryotic cellular organization similar to that of eubacteria, it is reasonable to propose that their cell division requires an FtsZ homolog derived from the common ancestor of all living cells (44).To gain insight into FtsZ evolution and diversity, we have isolated and determined the nucleotide sequence of an ftsZ gene from the extremely halophilic archaebacterium Halobacterium salinarium, which grows as long, rod-shaped cells. We show that H. salinarium ftsZ is remarkably similar to the eubacterial versions, particularly in the region most similar to tubulins. An alignment of the H. salinarium FtsZ sequence with those of eubacterial FtsZ proteins and tubulins suggests that H. salinarium FtsZ is more related to tubulin than are the eubacterial FtsZs, supporting the idea that tubulin may have evolved from FtsZ. We also show that H. salinarium ftsZ is not flanked by genes normally found adjacent to several known eubacterial ftsZ genes. Finally, we show that expression...

The European Nucleotide Archive (ENA; https://www.ebi.ac.uk/ena), provided by the European Molecular Biology Laboratory's European Bioinformatics Institute (EMBL-EBI), has for almost forty years continued in its mission to freely archive and present the world's public sequencing data for the benefit of the entire scientific community and for the acceleration of the global research effort. Here we highlight the major developments to ENA services and content in 2020, focussing in particular on the recently released updated ENA browser, modernisation of our release process and our data coordination collaborations with specific research communities.