Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel gene encoding an adenylyl cyclase, designated cyaG, was identified in the filamentous cyanobacterium Spirulina platensis. The predicted amino acid sequence of the C-terminal region of cyaG was similar to the catalytic domains of Class III adenylyl and guanylyl cyclases. The N-terminal region next to the catalytic domain of CyaG was similar to the dimerization domain, which is highly conserved among guanylyl cyclases. As a whole, CyaG is more closely related to guanylyl cyclases than to adenylyl cyclases in its primary structure. The catalytic domain of CyaG was expressed in Escherichia coli and partially purified. CyaG showed adenylyl cyclase (but not guanylyl cyclase) activity. By site-directed mutagenesis of three amino acid residues (Lys(533), Ile(603), and Asp(605)) within the purine ring recognition site of CyaG to Glu, Arg, and Cys, respectively, CyaG was transformed to a guanylyl cyclase that produced cGMP instead of cAMP. Thus having properties of both cyclases, CyaG may therefore represent a critical position in the evolution of Class III adenylyl and guanylyl cyclases.
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PMID:CyaG, a novel cyanobacterial adenylyl cyclase and a possible ancestor of mammalian guanylyl cyclases. 1113 14

Sensing light is the fundamental property of visual systems, with vision in animals being based almost exclusively on opsin photopigments [1]. Rhodopsin also acts as a photoreceptor linked to phototaxis in green algae [2, 3] and has been implicated by chemical means as a light sensor in the flagellated swimming zoospores of the fungus Allomyces reticulatus [4]; however, the signaling mechanism in these fungi remains unknown. Here we use a combination of genome sequencing and molecular inhibition experiments with light-sensing phenotype studies to examine the signaling pathway involved in visual perception in the closely related fungus Blastocladiella emersonii. Our data show that in these fungi, light perception is accomplished by the function of a novel gene fusion (BeGC1) of a type I (microbial) rhodopsin domain and guanylyl cyclase catalytic domain. Photobleaching of rhodopsin function prevents accumulation of cGMP levels and phototaxis of fungal zoospores exposed to green light, whereas inhibition of guanylyl cyclase activity negatively affects fungal phototaxis. Immunofluorescence microscopy localizes the BeGC1 protein to the external surface of the zoospore eyespot positioned close to the base of the swimming flagellum [4, 5], demonstrating this is a photoreceptive organelle composed of lipid droplets. Taken together, these data indicate that Blastocladiomycota fungi have a cGMP signaling pathway involved in phototaxis similar to the vertebrate vision-signaling cascade but composed of protein domain components arranged as a novel gene fusion architecture and of distant evolutionary ancestry to type II rhodopsins of animals.
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PMID:A rhodopsin-guanylyl cyclase gene fusion functions in visual perception in a fungus. 2483 57

This study sought novel ionizing radiation-response (IR-response) genes in Caenorhabditis elegans (C. elegans). C. elegans was divided into three groups and exposed to different high doses of IR: 0 gray (Gy), 200 Gy, and 400 Gy. Total RNA was extracted from each group and sequenced. When the transcriptomes were compared among these groups, many genes were shown to be differentially expressed, and these genes were significantly enriched in IR-related biological processes and pathways, including gene ontology (GO) terms related to cellular behaviours, cellular growth and purine metabolism and kyoto encyclopedia of genes and genomes (KEGG) pathways related to ATP binding, GTPase regulator activity, and RNA degradation. Quantitative reverse-transcription PCR (qRT-PCR) confirmed that these genes displayed differential expression across the treatments. Further gene network analysis showed a cluster of novel gene families, such as the guanylate cyclase (GCY), Sm-like protein (LSM), diacylglycerol kinase (DGK), skp1-related protein (SKR), and glutathione S-transferase (GST) gene families which were upregulated. Thus, these genes likely play important roles in IR response. Meanwhile, some important genes that are well known to be involved in key signalling pathways, such as phosphoinositide-specific phospholipase C-3 (PLC-3), phosphatidylinositol 3-kinase age-1 (AGE-1), Raf homolog serine/threonine-protein kinase (LIN-45) and protein cbp-1 (CBP-1), also showed differential expression during IR response, suggesting that IR response might perturb these key signalling pathways. Our study revealed a series of novel IR-response genes in Caenorhabditis elegans that might act as regulators of IR response and represent promising markers of IR exposure.
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PMID:High-throughput transcriptome sequencing reveals extremely high doses of ionizing radiation-response genes in Caenorhabditis elegans. 3158 52