Disease relevance of Nos

• These findings show that NOS activity is required for a robust innate immune response to gram-negative bacteria, NOS is induced by infection, and NO is sufficient to trigger response in the absence of infection [1].
• Inhibition of nitric oxide synthase (NOS) increased larval sensitivity to gram-negative bacterial infection, and abrogated induction of the antimicrobial peptide Diptericin [1].
• Inhibition of NOS activity in the imaginal discs of Drosophila larvae results in hypertrophy of tissues and organs of the adult fly, whereas ectopic overexpression of NOS has the reciprocal, hypotrophic, effect [2].
• The heme and flavin-binding domains of Drosophila nitric oxide synthase (DNOS) were expressed in Escherichia coli using the expression vector pCW [3].
• Reducing NO levels should be beneficial in sepsis, but NOS inhibitors have had a checkered history in animal models, and one such agent increased mortality in a clinical trial [4].

High impact information on Nos

• Inhibition of NOS in larvae causes hypertrophy of organs and their segments in adult flies, whereas ectopic expression of NOS in larvae has the opposite effect [5].
• Localization of the maternally synthesized nanos (nos) RNA to the posterior pole of the Drosophila embryo provides the source for a posterior-to-anterior gradient of Nos protein [6].
• By contrast, misexpression of Nos protein at the anterior of the embryo prevents translation of the anterior morphogen Bicoid, suppressing head and thorax development [6].
• Truncated isoforms suppress the antiproliferative action of DNOS1 in the eye imaginal disc by impacting the retinoblastoma-dependent pathway, yielding hyperproliferative phenotypes in pupae and adult flies [7].
• The NOS inhibitor L-NAME, the NO scavenger PTIO, the sGC inhibitor ODQ, and methylene blue, which inhibits NOS and guanylate cyclase, each caused the disorganization of retinal projections and extension of photoreceptor axons beyond their normal synaptic layers in vitro [8].

Chemical compound and disease context of Nos

• Full-length mouse nNOS proteins containing single-point mutations of Thr-315 and Asp-314 to alanine were produced in the Escherichia coli and baculovirus-insect cell expression systems [9].

Biological context of Nos

• Like mammalian NOSs, DNOS protein contains putative binding sites for calmodulin, FMN, FAD, and NADPH [10].
• The dNOS cDNA encodes a protein of 152 kDa, with 43% amino acid sequence identity to rat neuronal NOS [10].
• Alternative splicing affects both the 5'-untranslated region and the coding region of the dNOS primary transcript [11].
• Alternative transcription start sites and alternative splice sites are used to generate a remarkable variety of mRNAs from the dNOS gene [11].
• We cloned and analyzed the only gene in the fly genome that encodes Drosophila nitric-oxide synthase (dNOS) [11].

Anatomical context of Nos

• Throughout this period, the optic lobes show NADPH-diaphorase activity and stain with an antibody to nitric oxide synthase (NOS) [8].
• We show here by reverse-transcription polymerase chain reaction that Drosophila NOS (dNOS) is expressed in Malpighian tubules [12].
• In Drosophila, maternal Nos protein maintains transcriptional quiescence in the germ-line progenitors or pole cells to repress ectopic expression of somatic genes [13].
• Interestingly, Nos protein is localized to RNA granules in the dendrites of da neurons, raising the possibility that the Nos/Pum translation repression complex operates in dendrites [14].
• Using a regulated Drosophila cell-free translation system, we showed that ribosomes contained within these polysomes are capable of elongation in vitro, under conditions in which synthesis of Nos protein is repressed [15].

Associations of Nos with chemical compounds

• NO is synthesized from L-arginine by NO synthase (NOS) [10].
• Urea dissociation profile of DNOS full-length protein showed that the reductase domain activity was much more susceptible towards urea than the oxygenase domain activity [3].
• These data indicate that CAP2b stimulates NOS and therefore, endogenous NO production, which, in turn, stimulates a soluble guanylate cyclase [12].
• The oxygenase domain of the inducible nitric oxide synthase (iNOSox; residues 1-498) is a dimer that binds heme, L-arginine and tetrahydrobiopterin (H(4)B) and is the site for nitric oxide synthesis [16].
• Infection also leads to an increase in the kappaB-binding activity and up-regulation of immune-related gene expression, like inducible nitric oxide synthase and Factor C, an LPS-activated serine protease [17].

Other interactions of Nos

• Moreover, the N terminus, which is equivalent to beta-strand 1 in LC8, is splayed out and binds to a crystallographic dimer as an anti-parallel beta-strand at the same position as the neuronal nitric-oxide synthase peptide in the LC8 complex [18].
• Therefore, it was of interest to investigate if CAP2b acts through NO in isolated tubules and thus presumably through stimulation of a tubule NO synthase (NOS) [12].
• The control of dendrite morphogenesis by Nos/Pum, however, does not require hunchback, which is essential for body patterning [14].
• These pole cells expressed somatic markers ectopically and lost the germ-line marker Vasa. We further found that some Nos-negative pole cells were able to migrate into the gonads, but they failed to develop as functional germ cells during postembryonic stages [13].
• In macrophages, arginase competes with nitric-oxide synthase, which converts arginine into nitric oxide [19].

Analytical, diagnostic and therapeutic context of Nos

• DNOS activity is Ca2+/calmodulin dependent when expressed in cell culture [10].
• Using immunoprecipitation, we demonstrate that these short DNOS protein isoforms can form heterodimers with DNOS1, pointing to a physical basis for the dominant negative effect [11].
• The crucial roles of Asp-314 and Thr-315 in the catalytic activation of molecular oxygen by neuronal nitric-oxide synthase. A site-directed mutagenesis study [20].
• Using NADPH diaphorase staining and immunohistochemistry, nitric oxide synthase was localized in the parasitic nematode B. malayi [21].
• Nitric oxide synthase was detected by Western blot analysis of Brugia malayi extracts using an antibody raised against a peptide from murine brain nitric oxide synthase [21].

References