Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sweet potato chlorotic stunt virus (genus Crinivirus) belongs to the family Closteroviridae, members of which have a conserved overall genomic organization but are variable in gene content. In the bipartite criniviruses, heterogeneity is pronounced in the 3'-proximal region of RNA1, which in sweet potato chlorotic stuat virus (SPCSV) encodes two novel proteins, RNase3 (RNase III endonuclease) and p22 (RNA silencing suppressor). This study showed that two Ugandan SPCSV isolates contained the p22 gene, in contrast to three isolates of the East African strain from Tanzania and Peru and an isolate of the West African strain from Israel, which were missing a 767 nt fragment of RNA1 that included the p22 gene. Regardless of the presence of p22, all tested SPCSV isolates acted synergistically with potyvirus sweet potato feathery mottle virus (SPFMV; genus Potyvirus, family Potyviridae) in co-infected sweetpotato plants (Ipomoea batatas), which greatly enhanced SPFMV titres and caused severe sweetpotato virus disease (SPVD). Therefore, the results indicate that any efforts to engineer pathogen-derived RNA silencing-based resistance to SPCSV and SPVD in sweetpotato should not rely on p22 as the transgene. The data from this study demonstrate that isolates of this virus species can vary in the genes encoding RNA silencing suppressor proteins. This study also provides the first example of intraspecific variability in gene content of the family Closteroviridae and may be a new example of the recombination-mediated gene gain that is characteristic of virus evolution in this virus family.
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PMID:Analysis of gene content in sweet potato chlorotic stunt virus RNA1 reveals the presence of the p22 RNA silencing suppressor in only a few isolates: implications for viral evolution and synergism. 1819 89

Sweet potato (Ipomoea batatas) is an important subsistence and famine reserve crop grown in developing countries where Sweet potato chlorotic stunt virus (SPCSV; Closteroviridae), a single-stranded RNA (ssRNA) crinivirus, synergizes unrelated viruses in co-infected sweet potato plants. The most severe disease and yield losses are caused by co-infection with SPCSV and a potyvirus, Sweet potato feathery mottle virus (SPFMV; Potyviridae). Potyviruses synergize unrelated viruses by suppression of RNA silencing with the P1/HC-Pro polyprotein; however, the SPCSV-SPFMV synergism is unusual in that the potyvirus is the beneficiary. Our data show that transformation of an SPFMV-resistant sweet potato variety with the double-stranded RNA (dsRNA)-specific class 1 RNA endoribonuclease III (RNase3) of SPCSV broke down resistance to SPFMV, leading to high accumulation of SPFMV antigen and severe disease symptoms similar to the synergism in plants co-infected with SPCSV and SPFMV. RNase3-transgenic sweet potatoes also accumulated higher concentrations of 2 other unrelated viruses and developed more severe symptoms than non-transgenic plants. In leaves, RNase3 suppressed ssRNA-induced gene silencing (RNAi) in an endonuclease activity-dependent manner. It cleaved synthetic double-stranded small interfering RNAs (siRNAs) of 21, 22, and 24 bp in vitro to products of approximately 14 bp that are inactive in RNAi. It also affected total siRNA isolated from SPFMV-infected sweet potato plants, suggesting a viral mechanism for suppression of RNAi by cleavage of siRNA. Results implicate RNase3 in suppression of antiviral defense in sweet potato plants and reveal RNase3 as a protein that mediates viral synergism with several unrelated viruses, a function previously described only for P1/HC-Pro.
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PMID:Elimination of antiviral defense by viral RNase III. 1951 15

The I-CreI homing endonuclease from Chlamydomonas reinhardti has been used as a molecular tool for creating DNA double-strand breaks and enhancing DNA recombination reactions in maize cells. The DNA-binding properties of this protein were re-designed to recognize a 22 bp target sequence in the 5th exon of MS26, a maize fertility gene. Three versions of a single-chain endonuclease, called Ems26, Ems26+ and Ems26++, cleaved their intended DNA site within the context of a reporter assay in a mammalian cell line. When the Ems26++ version was delivered to maize Black Mexican Sweet cells by Agrobacterium-mediated transformation, the cleavage resulted in mutations at a co-delivered extra-chromosomal ms26-site in up to 8.9% of the recovered clones. Delivery of the same version of Ems26 to immature embryos resulted in mutations at the predicted genomic ms26-site in 5.8% of transgenic T(0) plants. This targeted mutagenesis procedure yielded small deletions and insertions at the Ems26 target site consistent with products of double-strand break repair generated by non-homologous end joining. One of 21 mutagenized T(0) plants carried two mutated alleles of the MS26 gene. As expected, the bi-allelic mutant T(0) plant and the T(1) progeny homozygous for the ms26 mutant alleles were male-sterile. This paper described the second maize chromosomal locus (liguless-1 being the first one) mutagenized by a re-designed I-CreI-based endonuclease, demonstrating the general utility of these molecules for targeted mutagenesis in plants.
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PMID:Male-sterile maize plants produced by targeted mutagenesis of the cytochrome P450-like gene (MS26) using a re-designed I-CreI homing endonuclease. 2411 65